Luminous Landscape Forum
Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: Nicolas86152 on October 04, 2005, 07:35:08 am
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Well, after all I red about the 5D I am not that shure to buy one.
There are several postings about the "vignetting-problem".
What are the real facts about 5D and vignetting.
If I could I would take some of my lenses (24TS, 90TS, 2,8/200 prime are my most used) and test it by my own, but there is no local dealer who has one to test ore to buy (and test before).
So this question is put to the persons who own already a 5D (I am not interested in speculations nor in getting teached optics): Is vignetting more visible than with film cameras?
Regards
Nicolas
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I can't think of any reason to expect that the problem is any greater than it would be with film. Correcting it using PS RAW reader is straightforward.
I upgraded from a 10D and am pleased. Mind you, its an incremental improvement even from a 10D. At this stage of the evolution of the technology, I believe it is hard to pull a slam dunk, better than slice-bread, gotta have 3 of them kind of camera. Bottom line? FF is wonderful for macro and WA, large files are great for printing larger prints but a drag when it comes to workflow, extra stop of sensitivity is much appreciated, color fidelity slightly better, ergonomics is better, and viewfinder is bigger but not brighter. Come to think of it, maybe I will get 2 more!
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Is vignetting more visible than with film cameras?
No. Vignetting will be exactly the same with a full-frame camera as it is with 35mm film. In the absence of film grain, you will find it easier to spot lens flaws such as chromatic aberration when shooting digital, but the degree of vignetting will not change. In any event, vignetting is easily corrected in any decent RAW converter, so it's really not an issue.
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@ Yoni
I would like to use a FF because mainly I am doing portraits. Pictures arent the same when I have to use 50 or 70mm instead of my 2,0/100-normal-lens with my 10D.
So FF at a moderate price is what I am looking for - there´s no need to convince me.
But for me it is important not to become a PS-artist. Hence there shouldn´t be too much manipulation needs.
@ Jonathan
"In the absence of film grain, you will find it easier to spot lens flaws such as chromatic aberration when shooting digital,..." Yes Jonathan, this could be a very important point to think of. The better the quality gets, the more obviouse become "not corrected things".
Could we bring your statement to the point "if vignetting is your only concern, don´t worry any longer and pull the bucks put of the pocket"?
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since vingetting is a function of the lens, not the camera, you only need to be cognizant of what the lenses you have do. this can be this can be shrewdly guessed by looking at the MTF charts for any given lens.
as was noted it is the nature of the full frame sensor to make any optical compromises in a lens more apparent. It is up to you to decide if those compromises are too much or negligable.
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since vingetting is a function of the lens, not the camera, you only need to be cognizant of what the lenses you have do. this can be this can be shrewdly guessed by looking at the MTF charts for any given lens.
as was noted it is the nature of the full frame sensor to make any optical compromises in a lens more apparent. It is up to you to decide if those compromises are too much or negligable.
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That's not quite right. There can be vignetting from the light hitting the sensor microlenses at an angle rather than head on. That is why some people think Nikon might have trouble with FF (the lens throat is smaller than the Canon EOS one).
There was a lot of hoo ha about sensor vignetting from the 5D but it looks as if it was in fact the 24-105 zoom that had severe vignetting wide open at 24mm.
Leif
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I wonder if they are fixing that while sorting out the flare problem, would be nice to dream...
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since vingetting is a function of the lens, not the camera,
Up to a point, but you will likely see more vignetting on a full 35mm size frame camera like the 5D than you will on a DX size sensor camera. Vignetting is a problem with full-frame dslr's because of the angle the light hits the wells in which each photosite sits. This wes never much of a problem with film. Its one of the advantages DX sensor cameras have, along with better edge of frame sharpness.
Quentin
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Up to a point, but you will likely see more vignetting on a full 35mm size frame camera like the 5D than you will on a DX size sensor camera. Vignetting is a problem with full-frame dslr's because of the angle the light hits the wells in which each photosite sits. This wes never much of a problem with film.
I've seen this statement made ever since the original 1Ds was announced, but I have yet to see a side-by-side comparison between a lens mounted on a film body and a full-frame digital body that actually showed more vignetting on the digital body than the film body. As far as I can tell, it's nothing more than an urban legend. Do you actually have a side-by-side comparison to support your statement?
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I've seen this statement made ever since the original 1Ds was announced, but I have yet to see a side-by-side comparison between a lens mounted on a film body and a full-frame digital body that actually showed more vignetting on the digital body than the film body. As far as I can tell, it's nothing more than an urban legend. Do you actually have a side-by-side comparison to support your statement?
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I would go one step further than GI Jo and state that the vignetting due to sensor design is a none issue and can be easily supported by looking at Phil Askey's review of the 5D in which he specifically tests for vignetting compared with a cropped camera. If the sensor was a source of vigentting in the image then it would still be apparent even when stopped down to f/11. As this is not the case we can argue (till we are blue in the face?) that the modern day sensor (can't speak for ancient Kodak SLRs) doesn't contribute to light fall off at the edges.
[Edit: Wanted to inlcude quentin's quote, but I am still struggling to understand the new forum software - aaaaaaaaagggghhh, is there more help than that included in the help file on the site? Like - what does the 'quote+' button do?]
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I would go one step further than GI Jo and state that the vignetting due to sensor design is a none issue and can be easily supported by looking at Phil Askey's review of the 5D in which he specifically tests for vignetting compared with a cropped camera. If the sensor was a source of vigentting in the image then it would still be apparent even when stopped down to f/11. As this is not the case we can argue (till we are blue in the face?) that the modern day sensor (can't speak for ancient Kodak SLRs) doesn't contribute to light fall off at the edges.
[Edit: Wanted to inlcude quentin's quote, but I am still struggling to understand the new forum software - aaaaaaaaagggghhh, is there more help than that included in the help file on the site? Like - what does the 'quote+' button do?]
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There are in fact cameras that demonstrate sensor vignetting. I am not sure if I remember the name right, but I think the 6MP Voigtlander rangefinder with interchangeable lenses that was introduced a year or so ago was found to suffer particularly badly. (Or was it Panasonic? Sorry to be so vague.)
But it does not seem to be an issue for the 5D.
It would not surprise me if Nikon unofficially encouraged such rumours.
Leif
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There is some vignetting, but I don't think it's excessive really.
This was taken on a 5D with a 16-35mm f/2.8 L, set to: 16mm @ f/4.
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If the sensor was a source of vigentting in the image then it would still be apparent even when stopped down to f/11.
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Not true: at larger apertures, the broader light cone means that some of the light reaching the corners of the frame strike the sensor at a more off-perpendicular angle than the principle ray, potentially producing more microlens vignetting than at small apertures. About an extra 10º at f/2.8 and an extra 21º at f/1.4.
Also, shifted lenses are mor prone to this than any normal lens, as they increase the off-pependicular angles. That is probably why most sensors for MF and LF backs continue to omit microlenses: to accomodate camera/lens motions like shift.
The trouble in detecting this is that there are three factors producing fall off at the corners: true vignetting, microlens vignetting, and "geometric fall off" with wide angle lenses.
- True vignetting is partial shading of the frame corners by the lens barrel, filters etc.
- Microlens vignetting is my name for the reduced sensitivity of sensors with microlenses to off-perpendicular light
- geometric fall-off is the fact that with almost any wide angle lens design and any sensor including film, light travels significantly further from the exit pupil to the corners of a wide angle frame than to the center, diminishing its intensity by the inverse square law. Near telecentric lens designs have no effect on this.
It might be that digital scrutiny has enabled detection of geometric fall-off that mostly went unnoticed with film. The Olympus E system includes software options for correcting "corner light fall-off" which is probably aimed at this effect, not microlens vignetting.
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There can be vignetting from the light hitting the sensor microlenses at an angle rather than head on. That is why some people think Nikon might have trouble with FF (the lens throat is smaller than the Canon EOS one).
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Irrelevant, and in fact the Nikon mount (along with Pentax and Minolta and Leica R mounts) is probably less prone to microlens vignetting than Canon mount, if such vignetting is an issue at all. Microlens vignetting is avoided by having the exit pupil far enough from the focal plane, in proportion to sensor diagonal length. Nikon mount and all the others mentioned above have the lens mount flange further from the focal plane than Canon EOS mount, likely meaning that their wide angle lenses have rear elements and exit pupils further from the focal plane. In fact measurements I have seen show that Nikon lenses in general have high enough exit pupils that microlens vignetting would not be an issue with a 35mm format sensor. From a collection of lens designs I saw in an optics text book, it seems that Canon stayed with more traditional near-symmetric lens designs for moderate wide-angle focal lengths while most others were using retro-focus (inverse telephoto) designs with higher exit pupils for almost everything wider than normal, but that information might be out of date.
Sigma lenses tend to have quite high exit pupils, so it might be interesting to compare Canon mount Sigma wides to Canon wides for evidence of microlens vignetting.
P. S. It continues to amaze me the number of easily refuted explanations going around for the decision of Nikon and their sensor partner Sony (along with Pentax and Konica-Minolta and Olympus and soon Panasonic and Samsung) to choose formats 16x24mm or smaller for their DSLRs. The obvious explanation it seems to me is an industry-wide consensus that the price/size/weight/performance trade-offs favor these new "digital specific" SLR formats for all but some relatively low sales volume, high end niches.
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I think the 6MP Voigtlander rangefinder with interchangeable lenses that was introduced a year or so ago was found to suffer particularly badly.
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It was the Epson rangefinder, and yes, rangefinder wide-angle lenses often use symmetric designs with far lower exit pupils than is possible with SLR lenses, making microlens vignetting a clear issue there. Note that this problem occurs even though the Epson's sensor is only about 16x24mm; vignetting would have been vert noticable with a 35mm sized 24x36mm sensor.
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It was the Epson rangefinder, and yes, rangefinder wide-angle lenses often use symmetric designs with far lower exit pupils than is possible with SLR lenses, making microlens vignetting a clear issue there. Note that this problem occurs even though the Epson's sensor is only about 16x24mm; vignetting would have been vert noticable with a 35mm sized 24x36mm sensor.
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Yes that's the beasty. Vignetting was seen to be serious IMO. Leif
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There is some vignetting, but I don't think it's excessive really.
This was taken on a 5D with a 16-35mm f/2.8 L, set to: 16mm @ f/4.
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I would call that pretty excessive compared to my 16-35L on my 20D.
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vignetting at f4 on my new 24-105L is bad compared to my 24-70L, showing at all focal lengths. The 24-70L clears up completely by 50mm, the 24-105L doesn't clear up at any aperture. Of course it's not comparing like to like, the 24-105 is wide open, the 24-70 is stopped down, but as I shoot at f4 as a standard for my wedding work, this is relevant for me. From 35mm on the 24-105 the vignetting seems uniform so I'll probably set up a profile in ACR for the vignetting and apply it to all the photos as standard, tweaking just the 24mm pics. The clarity and lack of any corner shading on my 85mm 1.8 at the same aperture makes me want to cry!
Here are two images shot at 50mm (the best focal length on the 24-105, for sharpness/contrast as well), the one with more vignetting is the 24-105.
(http://www.bphotography.co.uk/vig2.jpg)
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The only way to prove it would be to take photos of the same subject using the same lens, and both FF digital and film. Then compare the amount of vignetting in each case.
Leif
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I wonder if this can prove that vignetting is a function of the lens not the sensor ... Or does the amount the lens is stopped down make a difference to the sensor?
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To separate lens effects (god old fashioned vignetting and geometric fall off with wide angles) from sensor effects ("microlens vignetting"), you should compare at equal focal length and aperture. 85mm probably gives less of every kind of "corner fall off" than 50mm.
Yes, microlens vignetting can in principle get somewhat worse at larger apertures, when some light from the edges of the aperture reaches the corners at even more oblique angles.
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Both those shots showed 50mm in the Exif, here is the 24-105 with a similar field of view to the 85mm though in actual fact the Exif show that it is at 105, The distortion is interesting too. All shots were made from a tripod, same distance, etc. satisfied?
(http://www.bphotography.co.uk/vig3.jpg)
I use these lenses in the real world not on a test bench, no they arn't showing the same FOV even though they should, who cares, the 24-70 vignettes less than the 24-105 and the 85mm beats them both for the same FOV. So why is it now the microlenses, looks to me that it is the amount the lens is stopped down....
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All shots were made from a tripod, same distance, etc. satisfied?
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I think so: the zooms compared at 50mm is fine, and 24-105 @ 85 vs 105 sounds fine. (But are you really saying that the 24-105 at maximum focal length is really only 85mm? Zooms often overstate their maximum focal length a bit, but that 20% gap sounds extreme.)
Anyway, I would agree that from your experiments and at those focal lengths (and f/4), "microlens vignetting" is unlikely to be the culprit. The place that "MLV" is most expected is wide angles.
If you really want to do the experiment, I am afraid you must acquire a good 24mm prime, for comparison to the 24mm end of each of your zooms! Better yet, a 17-40 and 16-35, and a Zeiss or Nikon 20mm prime to compare to, since I believe that those ultra-wide zoom lens designs are more likely than the 24-70 or 24-105 to have a low exit pupil height, risking MLV, while the Zeiss and Nikon are likely to have a higher exit pupil than a Canon 20mm prime, minimizing MLV. (This is getting a bit like hunting the snark.)
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I've been shooting with the 5D and both the 24-105L & 24-70L, don't care about exacting tests, it's blindingly obvious that the 24-105L vignettes at all focal lengths until f8 and pretty horribly at 24mm f4.
The 85mmvs105mm also shocked me, didn't think that the difference would be so drastic. It was a subject at a distance of a meter and since the focal lengths are based on infinity it probably doesn't get much worse than that, I hope!
You did point out the difficulties with making a proper scientific test. it is worse than that as I've been finding out comparing the two 24-XL zooms. For a start the 24-70L backfocuses and the 24-105L front focuses slightly. Therefore for an accurate test you would need manual focus using a magnifier and even then, who is to say that your manual focusing is spot on? The focal lengths don't match up making getting equal FOV to be a nightmare, especially with the added distortion of the 24-105L, in other words, I give up!
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Isn't that when those nasty D2x nightmares start to haunt you again?...
Just pulling your leg.
How do you like the 5D otherwise?
Regards,
Bernard
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I would call that pretty excessive compared to my 16-35L on my 20D.
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Indeed, I have no problems believing you!! OTOH, on your 20D, 16mm is like 26mm and would therefore be much less prone to vignetting - that's one way to look at it. Another would be that your 20D discards the edges of the image and only records the middle, so you do not see the vignetting. Eitther way, what are we talking about here?
In fact, vignetting is not even an issue with a 20D... is it? So your comparison is meaningless! Now, comparing what this lens looks like on a 5D to what it looks like on film would be a comparison worthy of interest!
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How do you like the 5D otherwise?
First canon camera I owned (D60,10D,1Ds,5D) that exposed properly in Av mode. My auto flash is also spot on which makes me think that the iso is accurate for once! The WB is also the best I've ever seen from a canon camera, even ambient+flash is spot on. I would trust this camera to shoot JPG if I had to and I'm a hardened RAW fanatic! The DR is much better than I've seen, I'm not having to compress highlights to get a film like response for portraiture which is unusual. The colours are also far better for me than with the 1Ds, I don't see a need to custom profile which was a necessity with the 1Ds.
My complaints:
Jaggies are visible on angled lines when viewing at 100% in either ACR or DPP, quite annoyed about that, hopefully the fully supported next version of ACR will deal with that.
To make the most of the noise advantages you still need to expose to the right, the noise is similar to my 10D, BUT, the 100% of the 10D and 5D are vastly different, i.e. you would need to print much bigger to notice noise you would have seen on a small print from the 10D. There is thank G-d no banding in the blacks like the 1Ds was plagued with if you underexposed even slightly.
RAW images still take about 2 secs to come up for review though they are instantaneous in playback. Bit disappointed in that. Zoom is smooth and fast and the joystick is a pleasure to use for playback. Writing to the Sandisk Ultra II is so fast I hardly notice it.
The AF points are far too close together and could be marked better, in low light it's hard to diffrentiate between the thin squares. I'm seriously thinking of marking the center one with a pencil if I can confirm that it won't screw up the metering. AF is fast though for low light I've never noticed a difference between the 1Ds and 10D, the D2X defines what fast low light AF is! Choosing AF points with the joystick is easy enough. Press once for center point, again for auto choosing, wiggle to choose an individual point.
Battery life is disappointing, I'm not counting on much better than the 1Ds/10D which isn't good, no doubt the huge screen takes its toll, ditto the larger mirror. Still no excuse though.
Viewfinder is a FF viewfinder, can't say it's noticeably any better than on my Elan II, eye relief is crap for glasses wearers like me (isn't that all modern SLR's?). Lot better than a crop viewfinder though.
The resolution is absolutely fantastic but at higher iso's make sure the exposure is correct as the resolution goes down hill very fast with underexposure from iso800+
Other than that, it's a 20D with FF and better ergonomics, nuff said.
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First canon camera I owned (D60,10D,1Ds,5D) that exposed properly in . . . SNIP . . . .
Pom. Great information, eventhough I own a 20D and have no plans yet to upgrade. Just wanted to say nice info.
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Pom,
well, after some detours, someone finally gave a good answer to the original question of this thread!
Onto another detour, about VF magnification and image size. Maybe it is time for Nikon to follow Olympus in offering an auxiliary VF magnifier of 1.2x or 1.4x. Just 1.2x would bring the D2X and D200 VF magnification up to about 1.1x@50mm and thus bring their VF image size up to that of Canon's 35mm format SLR's like the 5D, with its 0.71x@50mm. (DX format needs 1.5x more VF magnification for the same VF image size.) Lenses used would need to be adequately bright to handle the dimming effect extra magnification, about one stop brighter than 35mm format lenses, so this could be too much magnification with f/5.6 lenses or low light conditions. That is why an auxiliary magnifier might be better than having a built-in magnification of 1.1x.
Strangely, the D200 has a distinctly higher magnification (0.94x) than the D2X (0.86x). The sub-35mm format DSLRs now seem to be settling in the range 0.9x-1x; maybe that is as high as it is safe to go without getting too dim, at least with slower lenses.
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I suppose it depends on the dimming effect but if someone made after market VF's that did this, like a slide on diopter eye shade, they could make a killing selling to the 1.5/6 crop market. The wow effect should outway the realisation of the dimming. Evenso, the trade off between straining your eye to see the postage stamp, and straining to see a darker screen though much larger might be worth it, bit like accepting f4 lenses over f2.8 for the weight gain.
BTW I didn't want to be a naysayer over this camera, it's certainly a good picture making machine and the wow reviews are all over the internet, mostly justified. I just wanted to point out a few niggles that I've noticed as a working pro. There are still some things about the whole canon system that I would love to see addressed. In corespondence with Chuck Westfall on Rob Galbraith he admited that the tying of exposure to the active focus point was a pain for us wedding photographers and hinted that a new CF could be along in the future which would give focus and exposure lock, in all modes with a half shutter press. He also told me that canon were looking for ways to impliment MLU in a more user friendly fashion and that my suggestion of putting it in the 'drive' menu would be passed along to the techs.
I'm looking forward to the grip and grid focus screen (the outer lines of the grid are perfect framing lines for a 8X10" + the grid is great for landscape work!), I can't say I enjoy shooting with two fingers hanging in space. My RRS L bracket is on the way as is a 580ex flash as I finally try ETTL again, I've only had ETTL I cameras till now hence the dependance on auto flash.
I have the 24-105L, if anyone wants to know, this lens is a huge bundle of compromises compared to the 24-70L but still has its niche.
Pros: Its lighter and smaller, it has IS.
Cons: Its f4 but still the same price, it's slightly less sharp at f4, the hood is nowhere near as good as the shading is less and the barrel is unprotected, the vignetting is not a joke and only clears up by f8 at all focal lengths, the distortion is also not nice at all, including at 50mm, the IS is a step back with no panning mode and no tripod auto sensing.
For me the IS is the reason I'm replacing my 24-70L for it (anyone want it? mint boxed £680 UK) It's also probably the reason I stayed with canon instead of going Nikon with the D200 (or two at that price!). In that I am somewhat disappointed in that the IS seems to have digressed with no panning mode (I pan a lot when shooting wedding work, dancing, etc), and canon is not clear whether IS will still work on a tripod. You don't want to come back from a trip abroad to find out that for all your tests, your best pics got screwed up because IS went slightly haywire. The IS is also not particularly fast to spin up. According to my tests, if you focus recompose then the lens needs 2 secs after recompose for IS to engage fully. Not that great if you shoot for the 'moment'.
Oh well, I saw a quote that said that photography is the art of the compromise...