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Author Topic: M8 Review - Looks great, BUT...  (Read 48823 times)
Ken
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« on: October 30, 2006, 11:01:02 AM »
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Like many old-timers, I have loved Leicas for decades. Michael's review had me itching for an M8. However... also like most old-timers, image stabilization is a real necessity. And, for everyone else, image stabilization would permit slower shutter speeds, enabling lower ISO, which would reduce or eliminate much of the noise of which Michael spoke.
« Last Edit: October 30, 2006, 11:27:28 AM by Ken » Logged
DarkPenguin
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« Reply #1 on: October 30, 2006, 11:26:58 AM »
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IS is such a great tool for showing subject movement.
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jani
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« Reply #2 on: October 30, 2006, 01:15:36 PM »
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Oh, I agree with the desire for IS, but I think the Leica shooting style allows for very good shots without worrying about that.

I'm not squarely in the "I wish I owned one and all the lenses" camp, but I'd sure like to have a couple of weeks' worth of hands-on experience.
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« Reply #3 on: October 30, 2006, 01:42:04 PM »
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Like many old-timers, I have loved Leicas for decades. Michael's review had me itching for an M8. However... also like most old-timers, image stabilization is a real necessity. And, for everyone else, image stabilization would permit slower shutter speeds, enabling lower ISO, which would reduce or eliminate much of the noise of which Michael spoke.
[a href=\"index.php?act=findpost&pid=82908\"][{POST_SNAPBACK}][/a]

I'm also an olt timer, and in my film days used Leica M2, M3, and M4s. Most have found that they can hand hold an RF camera at much slower shutter speeds than an SLR because of no slapping mirror or auto diaphragm.
Michael may want to comment on this, as I noted on several of his M8 pics the shutter speed was aroun 1/45th sec.
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adias
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« Reply #4 on: October 30, 2006, 09:34:28 PM »
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I'm surprised that MR did not comment on the color finging easily seen on specular reflections and high-contrast dark-to-bright edges - I've seen it on every M8 shot posted on the Web. The problem is quite common in cheap digicams but unacceptable on a Leica. The problem becomes a non-issue if the shots are converted to B&W, but it would be shameful if the camera would only be capable of good B&W shots.
I see this as an M8 fatal flaw, most probably caused by the lack of an AA filter.
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michael
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« Reply #5 on: October 30, 2006, 10:07:23 PM »
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I've shot about 700 frames with the camera and haven't seen anything such as you describe.

Michael
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eatstickyrice
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« Reply #6 on: October 31, 2006, 06:34:24 AM »
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I've shot about 700 frames with the camera and haven't seen anything such as you describe.

Michael
[a href=\"index.php?act=findpost&pid=82994\"][{POST_SNAPBACK}][/a]


Michael, I've seen the problem in some photos on dpreview.com. It specifically showed up on the edges of some tree trunks. However, the person posting clarified that they were working with a pre-production unit. That said, I wonder if you might have time to post a few additional color shots that show off Leica's ability to get great edges with color? I like the ones you've put out on the luminous landscape site, but would enjoy and benefit from seeing some more color shots in the gallery.

Thanks in advance if you are able to find the time to do that. Thanks for the consideration if not.

Rick
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John Camp
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« Reply #7 on: October 31, 2006, 08:51:17 AM »
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I'm surprised that MR did not comment on the color finging easily seen on specular reflections and high-contrast dark-to-bright edges - I've seen it on every M8 shot posted on the Web. The problem is quite common in cheap digicams but unacceptable on a Leica. The problem becomes a non-issue if the shots are converted to B&W, but it would be shameful if the camera would only be capable of good B&W shots.
I see this as an M8 fatal flaw, most probably caused by the lack of an AA filter.
[a href=\"index.php?act=findpost&pid=82992\"][{POST_SNAPBACK}][/a]

The first downloadable RAW shot on Outback Photo showed this fringing on chrome, but Uwe was using white plaster walls as his highlight area, and the fringing took place on chrome surfaces that must have been 4-5 stops overexposed. No camera could hold that, without doing something truly weird.  (You can see the fringing on both cars at the bottom of the photograph, in the wheel spokes of the front wheels on the car on the right, and around the gas cap in the car on the left.) One of the members of the Leica Users Group used ACR to clean it up, and reposted the shot, showing no fringing, and estimated it took him about a minute to do it. Again, this was an extreme situation of severely overexposed chrome in bright direct sunlight, and was easily fixed with the most common post-processing software.

Sean Reid showed some mosaicing in a wicker basket, also easily fixed.

I can't wait to get the camera.

JC
« Last Edit: October 31, 2006, 08:52:20 AM by John Camp » Logged
Gabe
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« Reply #8 on: October 31, 2006, 10:12:45 AM »
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image stabilization is a real necessity. [a href=\"index.php?act=findpost&pid=82908\"][{POST_SNAPBACK}][/a]

I'd say it's a real nicety, but "necessity"? Not so much.. Many many many very fine low-light, hand-held photographs have been produced on Leicas, and I can't see how the move to digital would change that possibility. As others have mentioned, these cameras are very easy to hold steady. That said, I'd take it in a heartbeat if it were being offered  

After reading the review, I think I might just get in line for one of these myself..

(BTW, I absolutely love the front-page image, Michael)
« Last Edit: October 31, 2006, 10:15:00 AM by Gabe » Logged
adias
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« Reply #9 on: October 31, 2006, 10:32:46 AM »
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The first downloadable RAW shot on Outback Photo showed this fringing on chrome, but Uwe was using white plaster walls as his highlight area, and the fringing took place on chrome surfaces that must have been 4-5 stops overexposed. No camera could hold that, without doing something truly weird.  (You can see the fringing on both cars at the bottom of the photograph, in the wheel spokes of the front wheels on the car on the right, and around the gas cap in the car on the left.) One of the members of the Leica Users Group used ACR to clean it up, and reposted the shot, showing no fringing, and estimated it took him about a minute to do it. Again, this was an extreme situation of severely overexposed chrome in bright direct sunlight, and was easily fixed with the most common post-processing software.

Color fringing is not only seen on that shot around chrome. It can be seen elsewhere, namely, the white painted graphics on the building's door glass. It will show up on on every specular reflection. It is due to the lack of an AA filter - a very unfortunate decision. Whoever hails designs without AA filters is dellusional and aims to deny basic physics. I'm sure this problem will be ovelooked as this camera is quickly becoming a fashionable must have toy.
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james_elliot
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« Reply #10 on: November 08, 2006, 12:37:20 PM »
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I just had a look at the wonderful review of the M8. However, I don't exactly understand what Michael says about the 8/16 bits issue of the Kodak sensor.
The M8 has a Kodak KAF-10500 sensor.
The spec sheet of the KAF-10500 says that the linear dynamic range is 71.5Db, with a note indicating that 71.5 = 20 log(Vsat/VN)
This means that log(Vsat/VN)=3.575
In log2 form, we hav log2(Vsat/VN)=11.88
Thus the sensor seems to be a 12 bits sensor, much like the sensors usually found on Nikon and Canon DSLR.
Am I wrong somewhere?
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« Reply #11 on: November 08, 2006, 12:44:46 PM »
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Color fringing is not only seen on that shot around chrome. It can be seen elsewhere, namely, the white painted graphics on the building's door glass. It will show up on on every specular reflection. It is due to the lack of an AA filter - a very unfortunate decision. Whoever hails designs without AA filters is dellusional and aims to deny basic physics. I'm sure this problem will be ovelooked as this camera is quickly becoming a fashionable must have toy.
[a href=\"index.php?act=findpost&pid=83063\"][{POST_SNAPBACK}][/a]

Sorry but you are wrong in my opinion.  I have used a Kodak 14nx (no AA filter) for over 3.5 years and now also use a Mamiya ZD (no AA filter as standard).  You can remove any color fringing quite easily, but you can't recover detail lost through the use of an AA filter.  I'm glad Leica realise this and have decided, rightly in my view, not to include an AA filter.

Quentin
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Quentin Bargate, ARPS, Author, photographer entrepreneur and senior partner of Bargate Murray, Law Firm of the Year 2013
BernardLanguillier
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« Reply #12 on: November 08, 2006, 07:40:18 PM »
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I just had a look at the wonderful review of the M8. However, I don't exactly understand what Michael says about the 8/16 bits issue of the Kodak sensor.
The M8 has a Kodak KAF-10500 sensor.
The spec sheet of the KAF-10500 says that the linear dynamic range is 71.5Db, with a note indicating that 71.5 = 20 log(Vsat/VN)
This means that log(Vsat/VN)=3.575
In log2 form, we hav log2(Vsat/VN)=11.88
Thus the sensor seems to be a 12 bits sensor, much like the sensors usually found on Nikon and Canon DSLR.
Am I wrong somewhere?
[a href=\"index.php?act=findpost&pid=84173\"][{POST_SNAPBACK}][/a]

James,

Per my limited understanding of these complex matters, DR has basically nothing to do with the bit depth.

1. DR can be expressed as a ratio in db, but it could also be expressed in decimal format as the Vsat/Vn ratio.

It just expresses the ratio between the brighest recordable illumination not resulting in blown highlights (saturated output current of the sensor), and the lowest illumination not producing a signal to noise ratio higher than a given value (impossible to distinguish between current resulting from actual image information and background current of the sensor).

It is usually expressed in log 2 form mostly because photographers are used to working with stops, and because a one stop increase corresponds to a doubling of the incoming light.

2. Completely independantly from this, you can decide to code the electric current coming out of the sensor photosites as a result of the incoming light any way you like.

Things in the digital world being discrete and based on binary arithmetics, the values of current are usually expressed as a binary number. The longer the number (bit depth), the more values you can use to describe the range of electric current correponding to the values between blown highlights and deep black, and the finer the division of the available range becomes.

You could very well decide to code using 16 bits a DR range corresponding to one stop only. Conversely, you could decide to only use 4 bits to express the same range.

Think of it as a ladder. The DR is how high the ladder is, and the bit depth is how many steps there are in the ladder.

Practically speaking, there seems to be little value in using very high bit depth to code a small DR, and using too few bits to express a large range would not do justice to the sensor's ability to output subtely different currents when small variation of illumination occur (especially when those changes of illumination occur in highlights or shadows).

Anyone else, please feel free to correct me.

Cheers,
Bernard
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james_elliot
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« Reply #13 on: November 08, 2006, 08:42:10 PM »
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James,

Per my limited understanding of these complex matters, DR has basically nothing to do with the bit depth.

1. DR can be expressed as a ratio in db, but it could also be expressed in decimal format as the Vsat/Vn ratio.

It just expresses the ratio between the brighest recordable illumination not resulting in blown highlights (saturated output current of the sensor), and the lowest illumination not producing a signal to noise ratio higher than a given value (impossible to distinguish between current resulting from actual image information and background current of the sensor).

It is usually expressed in log 2 form mostly because photographers are used to working with stops, and because a one stop increase corresponds to a doubling of the incoming light.

2. Completely independantly from this, you can decide to code the electric current coming out of the sensor photosites as a result of the incoming light any way you like.

Things in the digital world being discrete and based on binary arithmetics, the values of current are usually expressed as a binary number. The longer the number (bit depth), the more values you can use to describe the range of electric current correponding to the values between blown highlights and deep black, and the finer the division of the available range becomes.

You could very well decide to code using 16 bits a DR range corresponding to one stop only. Conversely, you could decide to only use 4 bits to express the same range.

Think of it as a ladder. The DR is how high the ladder is, and the bit depth is how many steps there are in the ladder.

Practically speaking, there seems to be little value in using very high bit depth to code a small DR, and using too few bits to express a large range would not do justice to the sensor's ability to output subtely different currents when small variation of illumination occur (especially when those changes of illumination occur in highlights or shadows).

Anyone else, please feel free to correct me.

Cheers,
Bernard
[{POST_SNAPBACK}][/a]
Yes, thank you, I understand that. I was just saying that with something like a 72.5Db (1:3758) as a ratio between Vsat and Vn, it was reasonable to encode it with 12 bits, like it is usually done. A good detailed explanation of what I wrote too scarcely is available there (look for "dynamic range"):
[a href=\"http://www.microscopyu.com/articles/digitalimaging/digitalintro.html]Fundamental etc...[/url]
Of course, Leica might have decided to encode the output of a 72Db CCD sensor with 8 bits, but then it's beyond my comprehension...

Cheers..
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BernardLanguillier
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« Reply #14 on: November 08, 2006, 10:42:30 PM »
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Yes, thank you, I understand that. I was just saying that with something like a 72.5Db (1:3758) as a ratio between Vsat and Vn, it was reasonable to encode it with 12 bits, like it is usually done. A good detailed explanation of what I wrote too scarcely is available there (look for "dynamic range"):
Fundamental etc...
Of course, Leica might have decided to encode the output of a 72Db CCD sensor with 8 bits, but then it's beyond my comprehension...

Cheers..
[a href=\"index.php?act=findpost&pid=84247\"][{POST_SNAPBACK}][/a]

James,

My bad. I had misunderstood the nature of your comment. 12 bits would indeed be a reasonnable value.

Regards.
Bernard
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Gary Ferguson
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« Reply #15 on: November 09, 2006, 12:04:16 PM »
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Surely this isn't the main issue with the M8, the really big M8 problem is IR spillage into the shot when used in artificial light. See here for an example

http://homepage.mac.com/billh96007/PhotoAlbum196.html

and here,

http://www.leica-camera-user.com/digital-f...o-box-goes.html

Apparently the ultra thin IR protective glass in front of the sensor means, under some conditions, black subjects (see the tuxedos and dresses in the above shots) become a ghastly magenta. Leica have said there's a solution, but it involves 6 bit coding on the lens, a special IR/UV filter on each lens, and a firmware update due late November. I'm relieved there's a solution in the pipeline, but I'm not sure it'll work for me. For example I'd planned on getting the forthcoming Zeiss M mount 21mm f4.5 for a light-weight Leica M8 travel outfit. Obviously a Zeiss lens can't have Leica coding. I'm fairly optimistic this will all be resolved before my M8 arrives in January 2007, but if it isn't I guess I'll cancel my order.
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Jack Flesher
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« Reply #16 on: November 09, 2006, 12:28:33 PM »
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Surely this isn't the main issue with the M8, the really big M8 problem is IR spillage into the shot when used in artificial light.

The key word in your statement above is "artificial light" -- and more specifically, artificial light high in IR or "hot" light.

I spent the past two days pushing this camera very hard to try and make it puke.

The simple fact is I can only generate the purple-toned blacks if shooting under "hot" tungsten, halogen or strobe (xeon) lighting.  It was *not* an issue under my CCT (cold cathode tube) continuous lighting nor under several types of indoor fluorescents I shot it under.

Moreover, I added an absorption-style IR cut filter (daylight version) and it fixed 99% of the IR bleed probelm -- to the point where I had to make some extreme image adjustments to find any IR hot spots in the shot.  I did not test it, but I am convinced had I used the stronger tungsten IR cut filter it would have totally eliminated the problem.

Since *my* use for the camera is almost exclusively outdoor,  I tried everything to make it fail under sunlight -- and couldn't.  I shot directly into the sun at ISO 1250, sun through trees, sun refelcting of of multiple colors of automobile paint, chrome, aluminum, house paints, fabrics, you name it and I shot it.  And I had absolutely zero issues with IR bleed.

My take on it is that if somebody is going to be using the M8 in a studio situation under direct hot lighting, then they probably have cause for concern.  If they are primarily outdoor shooters, it is essentially a non-issue.  

If they happen to shoot indoors under avaialable lightling it may be an issue especially if they are concerned about accurate color rendering -- however, even with film this was an issue and one needed to filter for it if they expected accurate colors.  And street and PJ photographers rarely bothered filtering their film for color-correct mixed lighting.

Personally, I think for most applications the M is going to be used for, this will be a small issue -- and if it a big one on occasion, you have the filter fix available.

My .02 only,
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bjanes
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« Reply #17 on: November 09, 2006, 01:09:08 PM »
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James,

Per my limited understanding of these complex matters, DR has basically nothing to do with the bit depth.

1. DR can be expressed as a ratio in db, but it could also be expressed in decimal format as the Vsat/Vn ratio.

It just expresses the ratio between the brighest recordable illumination not resulting in blown highlights (saturated output current of the sensor), and the lowest illumination not producing a signal to noise ratio higher than a given value (impossible to distinguish between current resulting from actual image information and background current of the sensor).

It is usually expressed in log 2 form mostly because photographers are used to working with stops, and because a one stop increase corresponds to a doubling of the incoming light.

2. Completely independantly from this, you can decide to code the electric current coming out of the sensor photosites as a result of the incoming light any way you like.

Things in the digital world being discrete and based on binary arithmetics, the values of current are usually expressed as a binary number. The longer the number (bit depth), the more values you can use to describe the range of electric current correponding to the values between blown highlights and deep black, and the finer the division of the available range becomes.

You could very well decide to code using 16 bits a DR range corresponding to one stop only. Conversely, you could decide to only use 4 bits to express the same range.

Think of it as a ladder. The DR is how high the ladder is, and the bit depth is how many steps there are in the ladder.


Anyone else, please feel free to correct me.

Cheers,
Bernard
[{POST_SNAPBACK}][/a]

Bernard,

I know your analogy of the ladder is also made by Bruce Fraser (I think he used a stair case), but I do not think it is correct. Current digital sensors use linear analog to digital converters and the potential dynamic range is limited by bit depth. Twelve bits can encode 4096 levels and 14 bits can encode 16,384 levels, giving DRs of 4096:1 and 16384:1 respectively. To demonstrate this, look at Norman Koren's chart and the text under the dynamic range heading.

[a href=\"http://www.normankoren.com/digital_tonality.html]http://www.normankoren.com/digital_tonality.html[/url]

A bit depth of 12 has a dynamic range of 9 zones (allowing for 8 levels in the darkest zone) and a bit depth of 14 gives 2 additional stops of DR. However, in practice the theoretical dynamic range is not reached as explained in this reference:

http://www.photomet.com/library_enc_dynamic.shtml

If the step size is fixed (with a geometric scale in this case), you need more steps to reach a given height. If a log AD converter were used, you could encode a greater DR with fewer bits and your analogy would be true.

Bill
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Gary Ferguson
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« Reply #18 on: November 09, 2006, 04:35:06 PM »
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The simple fact is I can only generate the purple-toned blacks if shooting under "hot" tungsten, halogen or strobe (xeon) lighting.

Jack, that's very interesting. Would the list of offending illumination include a regular flash like Leica's own unit?
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Jack Flesher
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« Reply #19 on: November 09, 2006, 06:39:17 PM »
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Jack, that's very interesting. Would the list of offending illumination include a regular flash like Leica's own unit?
[a href=\"index.php?act=findpost&pid=84379\"][{POST_SNAPBACK}][/a]

I didn't try a camera-mounted strobe, but I suspect it probably would also offend as most small strobes are xenon tubes too...  

(And I admit to a bit of personal bias here, given my old-school M roots -- I'll even go on record saying that a real M shooter does NOT use flash!  Handhold the thing at 1/8th if you have to and to heck with the little bit of blur!  )

Seriously, I think bottom line is if you want to use strobe or shoot a lot under hot lights AND you don't plan on converting the images to B&W, you will probably want to use the stronger lens-mounted IR cut filter (or your DSLR) in those situations.

Cheers,
« Last Edit: November 09, 2006, 06:46:07 PM by Jack Flesher » Logged

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