Ad
Ad
Ad
Pages: « 1 2 [3]   Bottom of Page
Print
Author Topic: True focus  (Read 9898 times)
Barry Goyette
Newbie
*
Offline Offline

Posts: 34


« Reply #40 on: February 14, 2010, 01:58:14 PM »
ReplyReply

Quote from: Esben
I would also like to mention that the camera felt like it had a softer mirror-slap, but that might just be me.
You got that impression too? That's how I felt...but considering there's been nothing about it in the literature, I figured it was just me.

On the supplying Raw files to the client. Now this is just something I almost never do...I really don't trust my clients to know what they are doing so I always, always, always insist on mastering out the file for them into either an 8 bit or 16 bit tiff. Part of this is really about controlling image quality...and also from the business side, it's essentially a mandatory add-on fee, and "while I'm at it, should I clean up her skin a bit?" Not as cynical as it sounds. The business of high end digital is not tilted in the favor of the photographer...best to take control of as much of the work as you can, IMHO. Hasselblad's proprietary software sort of acts as a "gatekeeper" for me. Most of my clients are quite happy that they get the image ready to go. (truth be told I'm also art director and designer on much of my client work...so I probably have less resistance than others to supplying a finished image)

Barry




Logged
Barry Goyette
Newbie
*
Offline Offline

Posts: 34


« Reply #41 on: February 14, 2010, 02:13:02 PM »
ReplyReply

Quote from: KevinA
Is this just Hasselblads round about way of saying we can't figure out how to do multi focus points, am I doing it disservice?

Kevin.

Yeah probably. I think hasselblad's argument goes like this...Developing a multi-point sensor for MF would be cost prohibitive. Canon and Nikon can spread out their R&D across millions of units...but MFD's total market is in the 10's of thousands. So what they would typically do is simply purchase a sensor unit from canon, or whoever is making it for them, but the problem is that sensor would do little more than cover the center of a mfd frame (at the demo they had some sheets showing a 35mm AF sensor pattern overlaid on a MFD frame). If you look at your 35mm..you'll see that the sensors are really clustered around the center anyway, but the problem is worse with mf. I think also that when you look at how MF is typically used in commercial applications, most or at least many photographers are either manual focusing or selectively autofocusing (focus/recompose) anyway...it's not like a sports camera where your hope is that one of the sensors locks onto a basketball player. The camera's aren't being used that way...the autofocus isn't fast enough really for that application...so typically you are using a hasselblad like you've always used a hasselblad...

That said, Hasselblad's AF is incredibly accurate, better than my eyes 100% of the time. This new feature will help in the 25% of the time when focus-recompose doesn't work well..and that is an improvement.

Barry


Logged
BJNY
Sr. Member
****
Offline Offline

Posts: 1112


« Reply #42 on: February 14, 2010, 07:27:15 PM »
ReplyReply

Quote from: Esben
I would also like to mention that the camera felt like it had a softer mirror-slap, but that might just be me.

Quote from: Barry Goyette
You got that impression too? That's how I felt...but considering there's been nothing about it in the literature, I figured it was just me.

David Grover, would you comment on this, please?

Thank you,
Billy
Logged

Guillermo
David Grover / Phase One
Sr. Member
****
Offline Offline

Posts: 951



WWW
« Reply #43 on: February 15, 2010, 03:40:35 AM »
ReplyReply

Quote from: Frank Doorhof
@David,
Ok,
I find that especially with the shallow DOF getting the focus perfect is more of a problem than with wide angles.
But for the movement it could be that with wide angles it's more obvious, don't know that.
I do know that I would "guess" it would be more of a problem with long lenses and shallow DOF.

F5.6 on MF is by the way giving you a very shallow DOF on 200mm.

Hi Frank,

Yes, you are certainly right in saying that with shallow DOF it is much harder for perfect focus.  Normally though, with a longer lens, your focus / recompose angle will actuallybe quite small, especially if you are a few metres from the subject. It then results in a very small TF correction.

Your issues probably come from other errors in the AF system or simply a model who dares to move 4mm after you have focussed!

David
Logged

David Grover
Business Support and Development Manager, Software.
David Grover / Phase One
Sr. Member
****
Offline Offline

Posts: 951



WWW
« Reply #44 on: February 15, 2010, 03:42:47 AM »
ReplyReply

Quote from: BJNY
David Grover, would you comment on this, please?

Thank you,
Billy

As far as I am aware no changes have been made to mirror mechanics.

It is probably because you read so much about 'mirror slap' here that you expect it to feel it more than there actually is!

Remember, you can also set a few ms delay on the leaf shutter firing after the mirror is UP, to help things.

D

Logged

David Grover
Business Support and Development Manager, Software.
KevinA
Sr. Member
****
Offline Offline

Posts: 898


WWW
« Reply #45 on: February 15, 2010, 08:04:54 AM »
ReplyReply

Quote from: bart alexander
Are other people fighting focus too, no matter what digital camera you're using?

Yes, especially with the 5DII (and 5D and D2X and D200). For exact focus I use live view and after nailed the focus with contrast AF, I just go along with shooting normally with the AF off, since I don't need it anymore for the same shot. (This is in the situation you described.) The 5DII is known for having a great central AF sensor and bad outer sensors, so why aren't you shooting a 1Ds3 which is supposed to have better outer AF sensors, or even better why not use a Nikon D3X which is supposed to be AF king? The one and only digital camera that always and always focussed dead on, was the Kodak 14n. Too bad it was so slow and had other issues too. But it nailed focus on any lens. No calibration nonsense at all, really amazing.

This focus issue with modern digital cameras has taken away a lot of the fun for me shooting at all. The non aliasing filter 14n again was good fun shooting, but a lot of work getting the files worked on. So, I wonder, why is it so difficult for manufaturers to make a well focussing camera? The 40D is supposed to be a far better focussing machine than the more expensive 5DII Why is that? Well anyway, we'll have to shoot what's available here and now, or just go and do something else for fun I guess.

If I was focusing then recomposing I would set my Canon to focus only when the back button is pressed, focus on the eyes then recompose.I can't see any advantage over this method with true focus if it can not adjust for subject or camera back and forth movement.
And yes I never had focus issues with a Kodak SLR/n either, Canon has been a totally different story. I hope true focus works like a dream, I just can not see it being something you could rely on to get what you need as it is. A step in the right direction, but a big enough step to be truly useful, time will tell.

Kevin.
Logged

Kevin.
lisa_r
Guest
« Reply #46 on: February 15, 2010, 10:02:30 AM »
ReplyReply

Mark, you probably already know this, but did you put one of these in your 5D2?
That should help a lot in terms of making sure that what you see in the viewfinder is what shows up on the monitor. They are $40.
It makes the DOF you see through the viewfinder look more like 2.8, instead of f4. View is very slightly darker, but well worth it if you are using fast lenses with shallow DOF.

re:
http://www.bhphotovideo.com/c/product/5904...sion_Matte.html
Logged
lisa_r
Guest
« Reply #47 on: February 15, 2010, 10:07:48 AM »
ReplyReply

And I agree, these 1600 ISO samples look awesome.

(nice that people are finally able to focus on what this camera has to offer, instead of obsessing over what it does not ;-))
Logged
Ajoy Roy
Jr. Member
**
Offline Offline

Posts: 60


« Reply #48 on: February 15, 2010, 10:47:44 AM »
ReplyReply

Quote from: David Grover / Hasselblad
Hi Kevin,

The problem with multi point AF on medium format is that placing the points so wide from the centre of the less would very much reduce the accuracy.  Especially if you wanted to use a short depth of field.  You could argue at tighter apertures that the issue would be dissolved of course.

Its not that we don't 'want' to do Multi Point AF, it is just trying to find a way that would ensure the same level of accuracy towards the edge of the optics as compared to the centre.

The off-the-shelf available AF sensors do not have wide enough spaced points for MF.  If you place a D3 AF sensor in an H4D50, you actually would get very little benefit even from the widest spaced points.  Also the AF sensor being an optical component itself is quite physically large, so tripling up the existing sensor is not possible and we would still have the accuracy issue.  Then of course you would also need to include an active LCD in the viewfinder describing which point you were using.

So right now the alternative is True Focus.  I have attached two PDF's which describe how the function is used (if interesting) and one which goes a bit more in-depth on where it matters.

I hope that helps.

Best



David

As the issue of multipoint AF comes up regularly in almost all MF forums, perusal of the Nikon AF technical brief could clear up a lot of quries - http://www.nikon.com/about/technology/core...e/caf/index.htm

Briefly
1. The AF module is a separate optical piece, hence will have to be as large as the senor
2. Such large modules are not available off-the-shelf, hence some one has to develop it! I guess that given the low numbers of MF cameras involved (compared to 35mm DSLR) it would add quite a lot to the cost as well as to the bulk.
3. Finally as David pointed out it would require a liveview, which I believe is not feasible (as yet) with CCD

In conclusion till there is a third party Multipoint 645 AF developed and licenced, we have to live with the current single point AF with various work arounds like True-Focus!
Logged

Ajoy Roy, image processing
Frank Doorhof
Sr. Member
****
Offline Offline

Posts: 1519


WWW
« Reply #49 on: February 15, 2010, 11:26:53 AM »
ReplyReply

@David,
To be honest I never have focus issues, only when shooting with the RZ67ProII with low key lights at the end of the day.
I've been using center focus for as long as I can remember, but I hear a lot of photographers complaining about it, maybe I'm just oldfashioned but I believe that if people could do it 20 years ago we should be able to do it now with brighter viewfinders.

However I love progress.
So I hope that it drips down to Canon, Mamiya etc.
It's always good to have something that could help.

About models moving 4mm, that's indeed not done, we use superglue and gaffer tape for that.....
Logged
EricWHiss
Sr. Member
****
Offline Offline

Posts: 2373



WWW
« Reply #50 on: February 15, 2010, 01:33:43 PM »
ReplyReply

Regarding focus - I wish for something more along the lines of a bigger brighter viewfinder than I do fancy auto focus electronics.  Larger sensors and faster glass would make this possible.   I have a canon 5D2 and even with all the selectable points, I miss focus more than I'd like and rely on the live view feature - but this is the same as just using a bright viewfinder only a lot slower and I can't hold the camera to my eye.  So were MF manufacturers to come out with a multi-point AF, I'd probably have a similar satisfaction with it.  What would be awesome is some kind of EVF with the Canon eye tracking stuff (EOS 3?) - where the camera would sense where you are looking and zoom in and out at that spot with the push of a button.  But until that happens a big bright viewfinder would be just fine.
Logged

Authorized Rolleiflex Dealer:
Find product information, download user manuals, or purchase online - Rolleiflex USA
pschefz
Full Member
***
Offline Offline

Posts: 244


« Reply #51 on: February 15, 2010, 03:40:51 PM »
ReplyReply

i really wish now that i would have gone to that demo....mostly because i can't believe the 1600 iso quality.....
i looked at some "old" P30 files and they did not look that good at 200....i am serious.....this 1600 iso combined with 40mpix file blows the canons/nikon AWAY...incl the next unannounced models.....

which is why i have to see for myself....how the hell can hasselblad go from the performance of available backs to this? the samples of binned files from the p65+ are not even close...and smaller....

raw files from the leica S (same sensor family afaik) don't compare at all...even at 320....

so how on earth is this possible?

so if anyone can offer a raw file, i would be very happy....

can the back provide this quality only out of phocus? afaik aperture supports hass files and there is no way i would ever go back to any (leaf, hass, sinar or even C1) software other then full workflow solutions (aperture, LR)....the time saved is WAY too valuable to me....so the question is: is there a lot of software magic behind this wonder and would i have to use phocus to get those results?
Logged

schefz.com
artloch.com
Nick-T
Sr. Member
****
Offline Offline

Posts: 462


« Reply #52 on: February 15, 2010, 04:21:11 PM »
ReplyReply

Quote from: pschefz
i really wish now that i would have gone to that demo....mostly because i can't believe the 1600 iso quality.....
I'm very impressed by that sample, I think the "leap" forward must be due to two things. First off the sensor is the new Kodak "True sense" design which is less noisy and has better dyes and I guess a bunch of other techy stuff. Second I know the R&D boys in Denmark have been putting a ton of work into high ISO performance (they release a free firmware update not so long ago bumping existing backs by a stop), so I guess we are seeing the results of that as well.
Nick-T
Logged

EricWHiss
Sr. Member
****
Offline Offline

Posts: 2373



WWW
« Reply #53 on: February 15, 2010, 04:27:01 PM »
ReplyReply

Not too far off topic I hope, but I was really happy with the ISO 400 shots from my ixpress 528c in single shot and they only get better with the multishot.  Since I only recently aquired this back, I don't know if this was improved with firmware or not but its great and its clear Hasselblad is doing very well in this area.  I am sort of hoping that this new sensor will make its way into the CF series so that I might mount it on my Rollei.
Logged

Authorized Rolleiflex Dealer:
Find product information, download user manuals, or purchase online - Rolleiflex USA
Dustbak
Sr. Member
****
Offline Offline

Posts: 2359


« Reply #54 on: February 15, 2010, 04:48:23 PM »
ReplyReply

Doing multishot at 400ISO you will get totally rid of the color noise. What remains are grainy and very nice transitions. Absolutely lovely, not too many people know this or have even seen it.

Back on topic. The H4D40 looks promising indeed. I am sure I get a chance to give one a test ride one of these days.
Logged
tho_mas
Sr. Member
****
Offline Offline

Posts: 1696


« Reply #55 on: February 15, 2010, 05:39:49 PM »
ReplyReply

Quote from: pschefz
i looked at some "old" P30 files and they did not look that good at 200....i am serious.....
I wonder a little bit about that.
The above posted ISO1600 actually reminds me a little bit of... my P21+ at ISO800.
If you take pixel pitch and resolution into account this would still be an advantage of 2 stops in favor for the H40.
Be that as it may - I am also impressed by that high ISO shot.

As to your P30: maybe try a current version of Capture One as it renders the files less coarse.
Too, the noise reduction is very much improved.
« Last Edit: February 15, 2010, 05:46:22 PM by tho_mas » Logged
Barry Goyette
Newbie
*
Offline Offline

Posts: 34


« Reply #56 on: February 15, 2010, 11:14:14 PM »
ReplyReply

Quote from: Nick-T
I'm very impressed by that sample, I think the "leap" forward must be due to two things. First off the sensor is the new Kodak "True sense" design which is less noisy and has better dyes and I guess a bunch of other techy stuff. Second I know the R&D boys in Denmark have been putting a ton of work into high ISO performance (they release a free firmware update not so long ago bumping existing backs by a stop), so I guess we are seeing the results of that as well.
Nick-T
I'll go back and see if I can retrieve the rest of the files I shot that day. I did another series of shots, again handheld there on the 4th floor of Samy's, at all ISO's from 100-1600. My impression was that there was almost no difference between the 800 and 1600 shots (a few hot pixels showed up in the 1600, and the grain got a little more ragged) but otherwise the color and detail stayed about the same, and the overall noise level seemed unaffected. And while at 100 there is slightly finer detail, and, of course, considerably less noise, surprisingly there is little difference in terms of tonality and color between the default iso and the higher gain shots. I remember the days when I'd underexpose my ixpress 132c by a stop in good light and the skintones would posterize and go grey. I'm simply shocked at what this camera can do at 4 stops underexposed in a mix of flourescent and tungsten.

Barry

Logged
Pages: « 1 2 [3]   Top of Page
Print
Jump to:  

Ad
Ad
Ad