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Author Topic: Mark Dubovoy's Leica S2 Review  (Read 18686 times)
dfarkas
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« Reply #20 on: June 29, 2010, 09:40:00 AM »
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Quote from: guyharrison
I had a very nice demo at a Capture Integration event where I shot the S-2 for an hour or so, with a model and also landscape/cityscape scenes. A Phase One DF was also present and I used it, more than I expected.

There was a lot to love about the Leica (weather sealing, quality, handling, simplicity in shooting--regarding all of which Mark was dead on), but we need to get real.

The Leica is not faster or more accurate at focus than the Phase One, period. They are very similar in focus speed. From my demo, I would say that you would never get a shot with the Leica that you would miss with the Phase One due to either speed or accuracy issues. Both focus very well and very quickly in dim light. I was surprised at this because Leica was claiming that their focus was significantly and substantially better. It is better than the older Mamiya bodies, and better than my Contax 645 (in speed but not in accuracy), but not so as against the newest-generation Phase.

This does not even account for what happens when you recompose, as has been thoroughly covered in other posts. I can't comment on Hassy because one was not there for my use. However, I believe that, in theory, their method for compensating for re-composition might actually be the best focus system yet for a format limited to one-center-point focusing systems.

That being said, I do not see where focus-and-recompose has ever lead me, with any system, to have chronically unsharp or unacceptable pictures. This is true even with 35mm systems using 85mm 1.4 lenses wide open. Of course, no comparison at all between Canikon AF and any medium format system which are still completely primitive by comparison.

Guy,

If I recall, you wrote about this experience on the GetDPI forum back in December 2009. If you attended that CI event in early December down here in Miami, you used the same physical camera I had to test with for two weeks prior. This camera had pre-release firmware and Leica has since issued two major firmware updates, both of which improved AF performance (speed and accuracy). In fact the latest 1.0.0.16 firmware has noticeably improved on already good speed. Keep in mind that Mark Dubovoy wrote his review based on this latest firmware. I'd suggest trying out the S2 again in its current state to see the difference for yourself. If you are in Miami, I'd be happy to demo it for you.

David

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« Reply #21 on: June 29, 2010, 09:58:16 AM »
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Quote from: dfarkas
Guy,

If I recall, you wrote about this experience on the GetDPI forum back in December 2009. If you attended that CI event in early December down here in Miami, you used the same physical camera I had to test with for two weeks prior. This camera had pre-release firmware and Leica has since issued two major firmware updates, both of which improved AF performance (speed and accuracy). In fact the latest 1.0.0.16 firmware has noticeably improved on already good speed. Keep in mind that Mark Dubovoy wrote his review based on this latest firmware. I'd suggest trying out the S2 again in its current state to see the difference for yourself. If you are in Miami, I'd be happy to demo it for you.

David

David,

 This camera needs more happy shooters, rather than forum posts. In the end, the only thing which really advertises a camera is people **pro or not pro*** who say"I use this, it works for me".

 A good example of this phenomenon is the 5D2, which is far from perfect as a movie cam, but which has established its reputation as a useful and profitable tool by finding a large untapped target audience.. The M8/M9 also have a crowd of people who like the rangefinder experience.
 
 If you can find enough people like Mark or Erwin who enjoy the S2 experience, then the camera will fly. Find users who can benefit - but don't get into a fight with the others. I for one will value Guy's opinion of any camera at least as high as Mark's, because Guy has used a viewfinder to put his kids through college.

Edmund
« Last Edit: June 29, 2010, 09:59:45 AM by eronald » Logged
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« Reply #22 on: June 29, 2010, 10:29:59 AM »
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Quote from: dfarkas
If I recall, you wrote about this experience on the GetDPI forum back in December 2009. If you attended that CI event in early December down here in Miami, you used the same physical camera I had to test with for two weeks prior. This camera had pre-release firmware and Leica has since issued two major firmware updates, both of which improved AF performance (speed and accuracy). In fact the latest 1.0.0.16 firmware has noticeably improved on already good speed. Keep in mind that Mark Dubovoy wrote his review based on this latest firmware. I'd suggest trying out the S2 again in its current state to see the difference for yourself. If you are in Miami, I'd be happy to demo it for you.

We've also noticed modest improvement with the S2's focus with the aforementioned firmware updates on our dealer demo units. During the same period the DF body has also seen several firmware updates and has also improved modestly.

Both have much better autofocus than legacy medium format bodies.

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« Reply #23 on: June 29, 2010, 11:02:09 AM »
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Quote from: eronald
David,

 This camera needs more happy shooters, rather than forum posts. In the end, the only thing which really advertises a camera is people **pro or not pro*** who say"I use this, it works for me".

 A good example of this phenomenon is the 5D2, which is far from perfect as a movie cam, but which has established its reputation as a useful and profitable tool by finding a large untapped target audience.. The M8/M9 also have a crowd of people who like the rangefinder experience.
 
 If you can find enough people like Mark or Erwin who enjoy the S2 experience, then the camera will fly. Find users who can benefit - but don't get into a fight with the others. I for one will value Guy's opinion of any camera at least as high as Mark's, because Guy has used a viewfinder to put his kids through college.

Edmund


Edmund,

I have no intention of "getting into a fight" with anyone, nor discounting Guy's opinion. I was merely stating that Guy's experiences were based on a pre-production camera with pre-production firmware from 7 months ago, not on the current shipping version and offered to provide another demo to him so that he could judge for himself.

Many of our customers are very happy with the S2, both pros (yes, those who make their living shooting it) and advanced amateurs, most of whom never go on forums. We've had numerous customers trade in other MFD systems and switch over to the S2 for some of the advantages that Mark talked about in his article. For some, the smaller size and better handling was the most important factor. For others, stellar battery life and good LCD. And, others still, weather sealing or improved AF performance. You get the idea. Each photographer has his or her own priorities and what the final driver is in his/her decision making process will vary from one person to the next. In an ideal world, those who have actually made the decision to go with the S2 would post on forums like this one and share their experiences and reasons why.


David

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« Reply #24 on: June 29, 2010, 12:22:56 PM »
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Dear David:

Thank you for touching on a very important topic.

I am thankful for two reasons:

1. I have been quite frustrated in the past trying to obtain information directly from Hasselblad.  Many inquiries via phone, letter or email have either been left unanswered or simply dropped after a while.  The last time I tried to obtain information from Hasselblad (on the focusing system, no less), I could not get anyone's attention, so I ended up resorting to asking the top industrial sales person in the San Francisco Bay Area to please contact the Hasselblad rep on my behalf and then have him try and help us get the information.  It still took many weeks of pushing and prodding to get a few simple answers.

If you are the man we need to talk to on Hasselblad technical matters, welcome.  I am excited.  I would appreciate it if you send me an email with your contact data via the forum.  I will then respond in kind and we can begin a direct dialog.

2. The issues that you bring up are certainly important and we should get to the bottom of them.  As I mentioned in my article, one good source regarding the Leica autofocus system is a series of technical articles  published in Leica Fotografie International.  Another source regarding autofocus systems not being continuous was a number of conversations I had directly with PhaseOne/Mamiya technical personnel in their main office in the US. I tried to have the same conversation with Hasselblad and I called several times, but was unable to obtain any information.

My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system.  You are correct that this can be done continuously.  The issue is the mechanics of the lens itself.  You need quite a bit of torque to get the focusing system to start moving.  The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement.  When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.

So, here is what I have done:

After reading your post, I stayed up late last night until offices opened in Europe.  I have already made contact with the chief technical product manager for the S2 in Germany.  I have also sent a communication to the Chief Technical Officer at PhaseOne and I am waiting to hear back.  If you could contact the equivalent person at Hasselblad, let's get the information directly "from the horse's mouth" at the highest levels at all three companies and share it with our readers.

Best regards,

Mark
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ErikKaffehr
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« Reply #25 on: June 29, 2010, 01:50:22 PM »
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Mark,

I have seen the issue discussed in the description of the original Minolta AF-system, they adjust focusing speeds in some (possibly seven) different steps. I was thinking about this when I read your article. Talking about zones may have been the wrong wording. Lesson learnt, by you I guess.

I really appreciate your efforts to discuss some of the finer aspect of achieving maximal resolution, and also the energy you invest to clear the issues with manufacturers.

Now, some thoughts about testing.

1) We need to be careful with statements that contradict common sense. Take for instance the issue regarding DR. It would be very hard to make a feasible explanation that MFDBs can achieve several stops better DR than DSLRs. For one thing, DR is a technical term, known from signal processing and pretty well defined. The other issue is that would MFDBs have a 6 stop advantage in DR they would be able to work with 6-steps of underexposure. That is like saying that an MFDB would perform at 6400 ISO like a DSLR at 100 ISO, I have not yet seen any evidence that was the case.

2) We can talk about prints. Unfortunately, prints cannot be distributed over the net. Files can be distributed. Why don't you post a few images explaining your experience. Anyone really interested in your writing would be competent to print their own samples. Of course the images demand a lot of bandwidth, but you don't need to release the full image for download.

3) It's nice to use a subject anyone can reproduce. In the great 2006 MFDB shootout the test target included a one dollar (US ;-) bill and Macbeth (sorry X-rite) Mini Color Checker card, anyone can reproduce that!

Now, I'm really appreciate your writing. I'd love to like equipment that you have access to, but rental fees here in Sweden seem to be pretty stiff. So for me it is not feasible to make my own tests. Also it's very nice to have tests done by someone who has a broad experience, like yourself or Michael Reichmann.

Some readers, including myself, have made references to Erwin Puts's tests of the S2, also including the Leica M9. Mr. Puts obviously finds in his tests that the Nikon D3X is superior to the M9 regarding image quality. I have seen some remarks on this forum that discredit him as a camera tester. But what are the issues? Is there anything wrong in his methods??He publishes what he finds and give samples to prove/indicate his findings. What's wrong with that?!

Best regards
Erik


Quote from: dubomac
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system.  You are correct that this can be done continuously.  The issue is the mechanics of the lens itself.  You need quite a bit of torque to get the focusing system to start moving.  The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement.  When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.


Mark
« Last Edit: June 29, 2010, 03:14:32 PM by ErikKaffehr » Logged

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« Reply #26 on: June 29, 2010, 02:48:07 PM »
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Quote from: dubomac
Dear David:

Thank you for touching on a very important topic.

I am thankful for two reasons:

1. I have been quite frustrated in the past trying to obtain information directly from Hasselblad.  Many inquiries via phone, letter or email have either been left unanswered or simply dropped after a while.  The last time I tried to obtain information from Hasselblad (on the focusing system, no less), I could not get anyone's attention, so I ended up resorting to asking the top industrial sales person in the San Francisco Bay Area to please contact the Hasselblad rep on my behalf and then have him try and help us get the information.  It still took many weeks of pushing and prodding to get a few simple answers.

If you are the man we need to talk to on Hasselblad technical matters, welcome.  I am excited.  I would appreciate it if you send me an email with your contact data via the forum.  I will then respond in kind and we can begin a direct dialog.

2. The issues that you bring up are certainly important and we should get to the bottom of them.  As I mentioned in my article, one good source regarding the Leica autofocus system is a series of technical articles  published in Leica Fotografie International.  Another source regarding autofocus systems not being continuous was a number of conversations I had directly with PhaseOne/Mamiya technical personnel in their main office in the US. I tried to have the same conversation with Hasselblad and I called several times, but was unable to obtain any information.

My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system.  You are correct that this can be done continuously.  The issue is the mechanics of the lens itself.  You need quite a bit of torque to get the focusing system to start moving.  The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement.  When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.

So, here is what I have done:

After reading your post, I stayed up late last night until offices opened in Europe.  I have already made contact with the chief technical product manager for the S2 in Germany.  I have also sent a communication to the Chief Technical Officer at PhaseOne and I am waiting to hear back.  If you could contact the equivalent person at Hasselblad, let's get the information directly "from the horse's mouth" at the highest levels at all three companies and share it with our readers.

Best regards,

Mark

Sorry mark, the buck stops with you here.

The information you presented in your review is flawed and inaccurate. The best place to start would be to acknowledge that and then seek the correct info.

I would have thought that if you were looking for specific info such as focusing mechanisms, then the obvious place to start would be on the forum you are actually reporting for, which is obviously frequented by both Hassy & Phase employees.

Passing the buck does no one any service.
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« Reply #27 on: June 29, 2010, 03:13:13 PM »
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I would like to respond to Erik's post regarding autofocus in the hope of clarifying things further.

There seems to be another reason why autofocus systems are not continuous. The reason is as follows:

 Basically AF is done through Phase Detection.  The light beams are split into two images in the mirror and sent through prisms to the AF sensor.  The effect is similar to focusing with a rangefinder. The AF sensor itself is usually only a few pixels high and a few dozen wide.    What I think some engineers mean in terms of “steps” or "zones" has to do with the amount of detected sharpness required to be considered in focus. In other words, there is a small range or a "zone" where the system declares that focus is good enough.

Unfortunately, some people may have gotten confused thinking that "zones" means a few zones from close up to infinity.  We are talking about many zones here. The more stringent the zone requirement is, the sharper the image will be.  What might have been OK for film, or for an old digital back may not be sufficient for a top of the line Medium Format back today. Leica claims it is demanding more precise results from their AF sensor and therefore finer slices (if you want to call them that), in other words more zones.

Interestingly, if an image is farther away, it will have finer peaks and valleys of light on the AF sensor versus a close object. This might explain why long distance AF seems to be less accurate than mid-range AF in many cases.  I have had AF failures with both, Hasselblad and PhaseOne systems particularly with distant objects.  In my Leica tests, the AF system worked flawlessly.  I am sure the Leica AF system would eventually fail if I used the camera for a long time (nothing is perfect!), but my first impression is that it is better than the MF autofocus systems.

Mark Dubovoy
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« Reply #28 on: June 29, 2010, 03:23:10 PM »
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Mark,

Thanks for expanding the issue. Actually, I'd suggest that your findings about focusing may be worth another article. Thanks for sharing.

I presume that you have seen the two articles by Joseph Holmes:

http://www.josephholmes.com/news-sharpmediumformat.html
http://www.josephholmes.com/news-medformatprecision.html

I would be most interested in your views on Mr. Holmes findings.


Best regards
Erik


Quote from: dubomac
I would like to respond to Erik's post regarding autofocus in the hope of clarifying things further.

There seems to be another reason why autofocus systems are not continuous. The reason is as follows:

 Basically AF is done through Phase Detection.  The light beams are split into two images in the mirror and sent through prisms to the AF sensor.  The effect is similar to focusing with a rangefinder. The AF sensor itself is usually only a few pixels high and a few dozen wide.    What I think some engineers mean in terms of “steps” or "zones" has to do with the amount of detected sharpness required to be considered in focus. In other words, there is a small range or a "zone" where the system declares that focus is good enough.

Unfortunately, some people may have gotten confused thinking that "zones" means a few zones from close up to infinity.  We are talking about many zones here. The more stringent the zone requirement is, the sharper the image will be.  What might have been OK for film, or for an old digital back may not be sufficient for a top of the line Medium Format back today. Leica claims it is demanding more precise results from their AF sensor and therefore finer slices (if you want to call them that), in other words more zones.

Interestingly, if an image is farther away, it will have finer peaks and valleys of light on the AF sensor versus a close object. This might explain why long distance AF seems to be less accurate than mid-range AF in many cases.  I have had AF failures with both, Hasselblad and PhaseOne systems particularly with distant objects.  In my Leica tests, the AF system worked flawlessly.  I am sure the Leica AF system would eventually fail if I used the camera for a long time (nothing is perfect!), but my first impression is that it is better than the MF autofocus systems.

Mark Dubovoy
« Last Edit: June 29, 2010, 04:27:57 PM by ErikKaffehr » Logged

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« Reply #29 on: June 29, 2010, 03:40:36 PM »
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Quote from: aaron
Sorry mark, the buck stops with you here.

The information you presented in your review is flawed and inaccurate. The best place to start would be to acknowledge that and then seek the correct info.

I would have thought that if you were looking for specific info such as focusing mechanisms, then the obvious place to start would be on the forum you are actually reporting for, which is obviously frequented by both Hassy & Phase employees.

Passing the buck does no one any service.

Aaron,

Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.

The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.

What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.

So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of  the scientific method and how to apply it to researching and writing up a topic like this.

It appears that we all have something to learn on the subject.

Michael
« Last Edit: June 29, 2010, 04:33:13 PM by michael » Logged
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« Reply #30 on: June 29, 2010, 03:57:17 PM »
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Quote from: michael
Erik,

Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.

The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.

What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.

So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of  the scientific method and how to apply it to researching and writing up a topic like this.

It appears that we all have something to learn on the subject.

Michael

I completly agree with that statement !

I'm reading from a certain distance, sometimes posting some ideas, good or bad but I must say that I'm astonished by the witches hunting Mark is facing and how sensitive are these subjects.

Lu-La being my first and unique forum, I may be naive and unexperienced, in fact I accept the unexperienced but nothing naive. Yes, there is a lot to learn.

First and for most, in my experience of life at least, mistakes have always been the best masters I ever had.
Instead of barking against someone's mistake, you may want to thank for many reasons.

First, it gives you a magnificent opportunity to show your knowledge with kindness.

Second, from the beginning, Mark has received these 6 stops from the old topic...I knew that would emerge at one point or another.

If you can not forgive mistakes to the others you loose a great knowledge for yourself, and if you can not keep gentle and correct, then you simply loose elegance.

The tones of my posts in this thread reflects my overall feeling about certain content I've read.

A pitty.

Hope we we all learn from that and I thank Mark to give us this oportunity.


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« Reply #31 on: June 29, 2010, 03:59:41 PM »
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Wasn't the comment of "the buck stops..." posted by "Aaron" and not "Erik"?

Just hoping to keep "credits" where due.
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« Reply #32 on: June 29, 2010, 04:01:38 PM »
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what i dont get, as questioned before , is the dynamic range statement.
Marc: what gives you the idea that any of the current 35 mm ff cameras have a dynamic range of 7 stops at base iso ?
or do you refer to high isos here with the 35mm cams ?
« Last Edit: June 29, 2010, 04:04:22 PM by rainer_v » Logged

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« Reply #33 on: June 29, 2010, 04:26:56 PM »
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Michael,

I think that you are quoting the wrong person. I would never, ever write anything like that.

Also, I actually appreciate Mark's writing. What I have an issue with is more that some of hist statements seem to contradict expectations, at least mine. I have no issue with that but I'd like to see an explanation.

In a follow up posting, Mark essentially says that there are a lot of small things, that add up. I can take that, makes sense.

Also, there are a lot of posters on these forums who use MFDBs and they would certainly not invest in them for vanity. On the other hand, the quest for perfection may go a bit far. You have yourself gone into view camera using Rodenstock HR Digitars. Did the expected advantages materialize? Would be interesting to now.

Best regards
Erik
Quote from: michael
Erik,

Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.

The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.

What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.

So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of  the scientific method and how to apply it to researching and writing up a topic like this.

It appears that we all have something to learn on the subject.

Michael
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« Reply #34 on: June 29, 2010, 04:34:19 PM »
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Sorry, my comment should have been directed at Aaron, not Erik. My mistake, now corrected.

Michael
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« Reply #35 on: June 29, 2010, 04:37:14 PM »
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Hi,

I'm also asking the same question.

In my view there is a technical definition of DR (Full well capacity/Read noise) that may be not relevant to photography. In real photography it is my understanding is that shot noise dominates and thats about square root of detected photons. The number of detected photons should be proportional to the size of the sensor. So doubling the surface of the sensor would give about half a stop, but I may oversimplify that.

In addition I feel that the discussion is complicated by the fact that we would have most noise in the dark parts and tonality would normally be compressed in the darks as we apply some kind of shadow compression (toe characteristics) in both image processing and printing.

Best regards
Erik


Quote from: rainer_v
what i dont get, as questioned before , is the dynamic range statement.
Marc: what gives you the idea that any of the current 35 mm ff cameras have a dynamic range of 7 stops at base iso ?
or do you refer to high isos here with the 35mm cams ?
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« Reply #36 on: June 29, 2010, 04:38:00 PM »
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Great!

Still friends?!

Erik
Quote from: michael
Sorry, my comment should have been directed at Aaron, not Erik. My mistake, now corrected.

Michael
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« Reply #37 on: June 29, 2010, 04:51:09 PM »
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Quote from: rainer_v
what i dont get, as questioned before , is the dynamic range statement.
Marc: what gives you the idea that any of the current 35 mm ff cameras have a dynamic range of 7 stops at base iso ?
or do you refer to high isos here with the 35mm cams ?


I don't have a dog in this hunt but I don't understand these tests or comparisons.

No knock on Mark, but a photo of someone's backyard doesn't tell anyone very much.

The focus thing has been on going with digital, since we could see the images at 100% and though I have no doubt that digital is more difficult to achieve exact focus, I have or have used about every camera made and I can tell you that autofocus on anything (except maybe a Nikon D3/D700) is always very, very, very subject dependent.  

What is in dead focus for two hours can change in a heart beat with different subjects, lighting and/or just stepping back 6 ft. and I've got about 20 bazillion files to prove it.

As far as a dslr only has 6 stops of range I'm not so sure that one flies.  I've shot medium format next to dslrs for a few years and I see a difference in the files, sometimes in depth, or color, sometimes in shadow detail and sharpness, but never have I seen a 7 stop advantage from any camera system, or better put a 7 stop disadvantage.

What I don't understand about Leica, (and I wish them well) is how the hell they sell these cameras in the first place given the fact that lenses are very late and tethering by all accounts is enormously slow.  If Leica wants to shake the rich dentists paint brush I'd suggest addressing both of these points.

Still, what I'd love to see on any comparison is a test like the Zaguto people funded.    Sure it may have some bias given Zaguto sells bits for dslrs, but overall when you fill the room of "working" professionals I doubt seriously if everyone there has any agenda other than to find out the facts.

http://www.zacuto.com/shootout

That's the kind of test I'd like to see and would go a long way to making these threads more fact based than conjecture.

IMO

BC
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fredjeang
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« Reply #38 on: June 29, 2010, 04:56:41 PM »
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Quote from: ErikKaffehr
Hi,

I'm also asking the same question.

In my view there is a technical definition of DR (Full well capacity/Read noise) that may be not relevant to photography. In real photography it is my understanding is that shot noise dominates and thats about square root of detected photons. The number of detected photons should be proportional to the size of the sensor. So doubling the surface of the sensor would give about half a stop, but I may oversimplify that.

In addition I feel that the discussion is complicated by the fact that we would have most noise in the dark parts and tonality would normally be compressed in the darks as we apply some kind of shadow compression (toe characteristics) in both image processing and printing.

Best regards
Erik
Erik,

The biggest problem IMO, is that strick measurements are not applicable in real field photography and I would like to explain why.
The scientists measurements are giving a very small advantage in DR for the MF backs, that's one part.
1/2 - 1 stop is very little, almost insignificant and at the same time important.

My personal experience of designer in some advertising adgencies during many years, I have spent time in the post production task and the differences between files are clear.
The field, is that MF gives you a lot more room than 35mm, even an old 22mp MF. The difference is not little but huge, but only when you need to play on the extremes.

That is indeed more noticiable when you need to push or extract a lot from your file. Not only it gives you room, but the quality of this "room" is much cleaner at based isos,
specially in shadows. The result is that for certain applications and in extreme PP, MF is simply way ahead. For how much?
I mean, how much suggestives DR stops would I give to MF when it comes to the real task? In my experience I can see at least 4 stops difference in applications before the image starts to fall appart.

It's amazing what you can recuperate with these backs. (ok, I know that normally if we do the job right we shouldn't have to, but...)

Maybe it is not 6, but it is certainly not 1.

According to the focusing, (still do not understand why things are not in focus for some) you center a lot the comments on the lens, but with the resolution of the current backs, that is just a small pasrt of the equation.
Mirror is a real problem (I suspect to be the biggest issue), tripods also and the way you handle the lightning in the case of controled sources etc...
Correcting manually after re-framing.

Also, I've seen pros that often go over closing their diaph. Beleive it or not but it is more current that you may think. Shooting at f22 and then complain about the lack of sharpness quality...

Cheers.
« Last Edit: June 29, 2010, 05:23:55 PM by fredjeang » Logged
markowich
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« Reply #39 on: June 29, 2010, 05:09:29 PM »
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Quote from: eronald
Re. AF, the question is not only what can the camera measure, it is also what can the lens be set to by the camera's AF. In other words the design of the actuator on each lens comes into play.

I do think that Mark's review is a paper which the referees would like revised ....when I was organizing conferences, we would simply ask an author to take the referres's views into account, and the paper would usually get improved.


Edmund

in my professional world it would have been rejected by every knowledgable referee.
peter
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