Benchista
Which Tyler
Reged: 11/08/2000
Posts: 42233
Loc: Everywhere and nowhere, baby
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Riza, James has already linked to that thread, I think.
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Nick
www.nbrphoto.com
Light and Shade II - the new blog
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Lounge Lizard
Old Wrinkly
Reged: 17/01/2004
Posts: 17885
Loc: Cambridge, Cambridgeshire
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Yes, Riza, I'm aware of that one. It was posted by one of our own forum members. We are still probing this and discussing the issues (in an adult manner unlike elsewhere  )
Thanks
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Lounge Lizard
Success is the ability to go from one failure to another with no loss of enthusiasm.
Winston Churchill
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bagpuss
Sporadic Pam
Reged: 08/04/2006
Posts: 9330
Loc: Camulodunum
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Crikey... 
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 Ooooooo eeeeeeeeeeeeeeeeeeeeeeeee oooooooooooooooooooooooooo
In the beginning, the universe was created. This has made a lot of people very angry, and is generally considered to have been a bad move.
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robc
old hand
Reged: 05/01/2006
Posts: 1021
Loc: London
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Quote:
...The 70-300 IS problem that they are going to start recalling...
Dont want to hi-jack the thread but,...did I miss something somewhere?
What 70-300 IS problem?
I have one (am one of the few who actually managed to track one down!!). Anything I should know about?
Thanks
Rob
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Lounge Lizard
Old Wrinkly
Reged: 17/01/2004
Posts: 17885
Loc: Cambridge, Cambridgeshire
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See other thread.
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Lounge Lizard
Success is the ability to go from one failure to another with no loss of enthusiasm.
Winston Churchill
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Pascal_Parvex
newbie
Reged: 02/08/2006
Posts: 1
Loc: Büttikon, Aargau, Switzerland,...
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Well, I'm new to the forum, I did not read all the answers here, and I'm late, but here are three more samples for you to look at:
They were all taken with the 24mm 1.4L prime from Canon. The Exif Data is still there, if you are interested. They were all taken at 1.4 and 1/8000.
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Theo
newbie
Reged: 06/09/2006
Posts: 4
Loc: The Netherlands
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Hi, found this site earlier this day and these vignetting threads drew my attention. I'm a professional Dutch wedding/portrait photographer btw.
Before the 5D I used Nikon systems (D2X, D70s, D1) and also Fuji S2Pro and S3Pro which share the Nikon mount. These 5D's are my first return to Canon since the analog days.
Naturally I tested both my 5D's -earlier, not today  - and they react the same to the vignetting issue.
These are my testresults:
Canon 20mm/2.8 usm: Fine from F8 and up. F5.6 is still quite usable.
Canon 50mm/1.4 usm: Fine from F4 and up. F2.8 is still quite usable.
Canon 85mm/1.8 usm: Fine from F5.6 and up. F4 is still quite usable.
Canon 24-70/2.8 L usm: Fine from F5.6 and up. F4 is still quite usable. (70mm stays a bit behind compared to the other focal lengths).
Canon 70-200/2.8 L usm IS: Fine from F5.6 and up. F4 is still quite usable. (135mm and 200mm stay a bit behind compared to the other focal lengths).
To me these figures pose no real problem. I use flash (and use it well if I may say so) and would up the ISO before upping the aperture during ceremonies due to the desired DOF in these photo's.
As for correcting: since I always shoot RAW I have my images converted. Lately I use DXO for this; it corrects many things automatically during the conversion, e.g. chromatic abbreration but also vignetting! And does a good job at it too.
Theo
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BennyBoy
enthusiast
Reged: 10/09/2005
Posts: 297
Loc: Huddersfield
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Sigh, have you shot that 14L at 1.4 on a film body lately - guess what, it's called light fall off and will be there on any EOS film body too. It's physics, not the 5D.
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Lounge Lizard
Old Wrinkly
Reged: 17/01/2004
Posts: 17885
Loc: Cambridge, Cambridgeshire
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Quote:
Sigh, have you shot that 14L at 1.4 on a film body lately - guess what, it's called light fall off and will be there on any EOS film body too. It's physics, not the 5D.
Don't sigh so loudly. My testing has showed that the same lenses at the same apertures do show signs of vignetting on a film body but are nowhere near as bad as the 5D suggesting that the cause is the lens but that a digital sensor may exagerate the effect, as seems to be the case with the 5D.
Before I publish my findings, I need to repeat my film tests (weddings and holidays over the summer have got in the way) as the film camera I shot on had a sticky shutter and many frames were only half-exposed. However, there was sufficient information for me to arrive at my conclusion above.
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Lounge Lizard
Success is the ability to go from one failure to another with no loss of enthusiasm.
Winston Churchill
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Theo
newbie
Reged: 06/09/2006
Posts: 4
Loc: The Netherlands
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Hi Benny,
I don't have a 14mm lens, so maybe you replied to someone else's post instead of mine.
IF your message was a reply to my post, well, in that case I don't know what you are trying to get across.
Regards,
Theo
Ps
I'm well aware what vignetting is. My post only shows at what aperture the vignettting is gone for specific Canon lenses when used with a 5D.
Edited by Theo (07/09/2006 12:11)
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Theo
newbie
Reged: 06/09/2006
Posts: 4
Loc: The Netherlands
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Oh dear I now see the "quick reply" simply puts my answer to Benny's message under that of David...hmmm
Guess I better not use the "quick reply" anymore
Theo
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Dutch Photographer - people photography mainly.
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Benchista
Which Tyler
Reged: 11/08/2000
Posts: 42233
Loc: Everywhere and nowhere, baby
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Good call - Quick Reply is not very helpful!
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Nick
www.nbrphoto.com
Light and Shade II - the new blog
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Lounge Lizard
Old Wrinkly
Reged: 17/01/2004
Posts: 17885
Loc: Cambridge, Cambridgeshire
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Theo
I shoot weddings too and sometime do use apertures as low as f2.8 where I don't need good DoF or where I deliberately want a shallow DoF. So, the vignetting wide-open intially perturbed me. I now use DxO Optics Pro as well and think that it does a good job making the 5D usable at these apertures.
Though light fall-off is an optical effect, I feel that the design of the sensor magnifies this and it is an issue that camera-makers should address either by improved sensor design or by incorporating DxO-like software into the camera body.
Over many years of camera development, all optical quirks due to the laws of physics have been largely overcome. Vignetting or light fall-off has always been there but not enough to cause concern, until now. Consequently, I can see more R&D effort being needed to knock this one on the head. After all, digital introduced a new problem of dust on the sensor and solutions are starting to be introduced right now.
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Lounge Lizard
Success is the ability to go from one failure to another with no loss of enthusiasm.
Winston Churchill
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Theo
newbie
Reged: 06/09/2006
Posts: 4
Loc: The Netherlands
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David,
Of course I use low apertures as well. But not as often as I use F5.6
Anyway, until a week ago I shot with Nikon D2X. I used F5.6 the most, followed by F4 and F8. And those in their turn -at some distance- followed by F2.8 and F11.
Now with the 5D is a new ballgame. The dof of F5.6 on the D2X is about the same are the dof of F8 on the 5D, even a bit more. So I guess I will be using F8 a lot on the 5D followed by F5.6 and F11 etc. We'll see how this developes.
They might create lenses that deal with this vignetting but I'm afraid these lenses are going to be a bit costly. Time will tell.
I do have a question for you regarding the 5D Raw files and the DXO software:
When I used DXO on my D2X files, even the lenscorrections where performed for the lenses known to the software.
But now, with the 5D, using lenses known to DXO, the focusdistance appears to be missing in the exif data of the 5D files. Therefore DXO cannot perform lenscorrections on those files. I get a warning message about that everytime I have the 5D files converted. Bit of a pity. Is this your experience as well? Or is this a setting I'm missing?
Regards,
Theo
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Dutch Photographer - people photography mainly.
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BennyBoy
enthusiast
Reged: 10/09/2005
Posts: 297
Loc: Huddersfield
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I think any processing that gets done in camera is a Bad Thing(tm), best to leave it to post processing and the choice of the photographer (in RAW anyhow).
I do agree with you David that the sensor photosites/microlenses may have a contributary effect since they prefer light to be incident at 90 degrees to their surface - with most lenses being retrofused the angle of incidence can be quite acute (so I believe).
Until I see controlled tests shot in a studio with identical lighting and subject matter, I'll reserve judgement.
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TimF
Taking it strictly
Reged: 30/07/2001
Posts: 18965
Loc: Herts/Beds border
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Quote:
Though light fall-off is an optical effect, I feel that the design of the sensor magnifies this and it is an issue that camera-makers should address either by improved sensor design or by incorporating DxO-like software into the camera body.
As Leica already have with the DMR - all compatible R-series lenses were mapped by Imacon for correction of vignetting, distortion etc, obviously ROM lenses are needed to get the full benefits here - and from what I've heard the forthcoming M8 employs a similar internal solution, hence the "barcoding" that has been introduced for many lenses both current and old.
Quote:
with most lenses being retrofused the angle of incidence can be quite acute (so I believe).
I might be talking out my ass here, but surely a retrofocus wide angle should have a less severe angle of incidence than a non-retrofocus design, such as rangefinder wides (especially older ones which were around prior to in-camera metering), and (again) older mirror-up wide angles for SLRs. The basic point is undoubtedly true though, film is simply far more forgiving/versatile (delete according to preference!) in its response to the angle at which light strikes it.
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Tim BSRIPN
If I had all the money I've spent on drink, I'd spend it on drink
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BennyBoy
enthusiast
Reged: 10/09/2005
Posts: 297
Loc: Huddersfield
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You're probably right Tim, I may have my incidence back to front based on design - but that seems to be the main problem (which affects all digital sensors - just more pronounced at the edges).
A post higher up compared the 5D dof at f8 to that of the D2X at f5.6: That is precisely correct, the smaller sensor (and thus differing circle of confusion) is a direct factor in the perceived DOF of photos taken with a camera. I find myself shooting at f/8 to f/16 predominantly these days.
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TimF
Taking it strictly
Reged: 30/07/2001
Posts: 18965
Loc: Herts/Beds border
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Quote:
A post higher up compared the 5D dof at f8 to that of the D2X at f5.6: That is precisely correct, the smaller sensor (and thus differing circle of confusion) is a direct factor in the perceived DOF of photos taken with a camera.
I can't really agree with that conclusion. With film the frame size is a factor in determining how large a print can be made before the quality declines below acceptable levels, and CoC and DoF are part of that too. With digital, the maximum print size that is attainable (without ressing up) is determined by the number of pixels, and the output resolution chosen at post processing. So, in theory, prints of equal size and quality can be produced from a 6 Mp DSLR and a digicam of the same pixel count. In practice the DSLR will give a better print, especially at larger sizes, but that would be more to do with the size of the individual pixels.
So, IMHO, there is no direct correlation between CoC and DoF as there is with film. At least, not until you start making enlargements, ie, ressing up.
The real reason for the increased DoF with cropped frame DSLRs (and much more so with digicams) is simply due to the fact that the smaller frame size requires a shorter focal length lens to achieve the same angle of view. Many have noted that with a digicam it is almost impossible to have limited depth of field, even at f/2; hardly surprising though, seeing as these cameras typically have zooms of around 7mm to 28mm true focal length.
With the Canon 5D, you mount a 50mm lens to get a "normal" view. With the D2X (or similar cropped DSLRs) you need to use a 28mm or 35mm to get a similar AoV. The lens remains a 28mm or 35mm though, with the increased DoF over a 50mm that is the norm.
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Tim BSRIPN
If I had all the money I've spent on drink, I'd spend it on drink
Edited by TimF (08/09/2006 08:58)
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Malcolm_Stewart
Carpal \'Tunnel
Reged: 11/07/2005
Posts: 4459
Loc: Milton Keynes, UK
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Quote:
With the Canon 5D, you mount a 50mm lens to get a "normal" view. With the D2X (or similar cropped DSLRs) you need to use a 28mm or 35mm to get a similar AoV. The lens remains a 28mm or 35mm though, with the increased DoF over a 50mm that is the norm.
And the above, Tim, is the clearest exposition I've seen on this hoary old chestnut!
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Malcolm Stewart
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