mfurman wrote:
I am in a sense glad that you are experiencing the problem I was trying to interest others in, for quite a long time. As I mentioned, the problem (for my lenses) was also starting at 160 mm. I am still not sure if the issue is confined only to some copies or other users are more tolerant of softness.
I understand... There were many times I felt the same during my Nikon days when I found out my 80-200mm f/2.8 had the same problems.
I bought this lens (it is by the way absolutely excellent outside its limitations) for its maximum magnification (0.21), which can be only achieved at 200 mm.
I don't find this lens particularly good at micro level sharpness (over the entire range). For example, my 135L renders detail in a more delicate manner. I expect a macro lens would be better suited. But I agree, Canon advertises the lens has a MFD of 1.2m over it's entire focal range and a max magnification of 0.21 at 200mm provided you can get sharp pics at it's MFD
According to their specs, the MFD at 70mm is 1.2m and the MFD at 200mm is 3.9m!!!
This is a shocking statement. Where is it listed or even mentioned in their data sheets?
What about the maximum magnification. I think that Canon is crossing any boundaries of decency recently.
The tech had to look it up. But I also talked to a Canon rep today. He said he had never heard of this problem. Don't you hate how Canon reps try to make you think you are the dumb ass, instead of that there could be something wrong with the gear. Anyway, next week I let Canon Service take a look at my lens.
I also tested a little further today and got some decent sharp pics at 200mm / 1.4m FD :
REMOVED LINK (warning: big file - low JPEG quality)
and at 200mm / 2m FD:
REMOVED LINK (also big file - low JPEG quality)
In both pics I had flash and IS on. Both samples are rendered through Lightroom with no sharpening or any PP at all. Seems like there is a little backfocus going on. I focused on the nose (in very low light) and the hairs on top are the sharpest. In any case my initial findings of a MFD of 3m at 200mm were not accurate. I would say the pic shot at 2m FD is usable for large prints. The pic at 1.4m FD is suitable for medium sized prints.
Sometimes I think there is something not operating as it should be in the relation between the 5D's AF and the AF algorythms the lens uses. But this is pure speculation.
Anyway, to be continued.
Edited by Daan B on Feb 28, 2008 at 03:47 PM GMT (Reason: Removed links)
Curiosity got the better of me since I have a 70-200 f4 NON IS, and was seriously considering an upgrade to the IS version.
A quick test (tripod based, mirror locked up) says my NON IS version exhibits the same behaviour.
I get soft images at 160mm + FL when focused in the 1.2m (MFD) to 2m range.
Images are noticeably sharper at less than 160mm FL at the same lens to subject distance.
At 4m+ lens to subject distances this is a lens I would consider sharp -and I have a 200mm / 2.8 prime for comparison.
The prime has a 1.5m MFD and I shot the same test subject at this distance - the prime and zoom are comparable in sharpness when the zoom is at less than 160mm FL.
Ok Daan I ran a few simple test shots (IS off, ~ MFD, on tripod, triggered with wired remote), here's my findings (bear in mind I believe my copy backfocuses a little, a few mm for short focus distances)
- At 70mm it beeps if I half press the shutter on remote. Picture came out sharp.
- At 100mm it flashes but no beeping, shutter would not trip (no AF obtained), so I moved the tripod back away from the subject, about 1-2cm, then it beeped. So there was a tiny shift here. Picture came out sharp.
- At 135mm it beeped again, sharp result.
- At 200mm it beeped also, sharp result.
So the only MFD shift I experienced was from 70mm jumping to 100mm, and even so it was only 1-2cm. I don't know why Canon says MFD at 200mm can be about 3.9m !!!
Leon Noel wrote:
Ok Daan I ran a few simple test shots (IS off, ~ MFD, on tripod, triggered with wired remote), here's my findings (bear in mind I believe my copy backfocuses a little, a few mm for short focus distances)
- At 70mm it beeps if I half press the shutter on remote. Picture came out sharp.
- At 100mm it flashes but no beeping, shutter would not trip (no AF obtained), so I moved the tripod back away from the subject, about 1-2cm, then it beeped. So there was a tiny shift here. Picture came out sharp.
- At 135mm it beeped again, sharp result.
- At 200mm it beeped also, sharp result.
So the only MFD shift I experienced was from 70mm jumping to 100mm, and even so it was only 1-2cm. I don't know why Canon says MFD at 200mm can be about 3.9m !!!
Hope that helps , good luck and happy shooting. ...Show more →
Leon,
Thanks for sharing your test results Any change to post (or link to) some 100% crops?
I think a focus shift of 1-2cm can be considered normal.
About a 3.9m MFD at 200mm... I think he meant to say that MFD tolerances are between 1.2m at 70mm and 3.9m at 200mm. As we are seeing, it actually lies somewhere in between. With a lot of variation between samples I might add
Maybe we should start a poll to check who has the MFD problems and who doesn't. Even non-IS versions seem to suffer...
I've got a 70-200mm F4 IS speeding it's way toward me via UPS... Current status says it will arrive at my home tomorrow. Not sure how quickly I'll get to do serious testing of ALL it's abilities, but I should be able to do some quick tests tomorrow night...
I just returned a 70-200mm f4 non IS version, due to back focus... but it back focused more at 70mm then it did at 200, and it also back focused at focus distances well beyond it's MFD.
I can only say that my most recent copy was very sharp at 135 mm and MFD - I mean sharper than yours.
As far as 200 mm is concerned at focusing distance >2.8 my 70-200 was as sharp as I would ever want it to be. Here is one of the shots at 200 mm and a 1.4 teleconverter.
Can someone show me a Canon document which states the 70-200mm F4 IS USM lens is supposed to be able to focus as close as 1.2m at 200mm focal length? and/or that it's capable of 1:5 magnification? I've seen statements like that at some web sites, but not in a official Canon site or document.
Item Code: 2578A002
Specifications
Lens
Focal Length & Maximum Aperture
70-200mm 1:4.0 Lens Construction
16 elements in 13 groups
Diagonal Angle of View
34° - 12°
Focus Adjustment
Inner focusing system with USM
Closest Focusing Distance
1.2m / 3.9 ft.
Zoom System
Rotating Type
Filter Size
67mm
Max. Diameter x Length, Weight
3.0" x 6.8", 25 oz. / 76mm x 172mm, 705g
Those are not the specs for the 70-200mm F4 IS USM, and I can't find any specs that are that detailed about that lens at Canon's site. Not only that, even those specs do not say it can focus at 1.2m when it's at 200mm...
Item Code: 2578A002
Specifications
Lens
Focal Length & Maximum Aperture
70-200mm 1:4.0 Lens Construction
16 elements in 13 groups
Diagonal Angle of View
34° - 12°
Focus Adjustment
Inner focusing system with USM
Closest Focusing Distance
1.2m / 3.9 ft.
Zoom System
Rotating Type
Filter Size
67mm
Max. Diameter x Length, Weight
3.0" x 6.8", 25 oz. / 76mm x 172mm, 705g
Edited by DynoMoHum on Feb 21, 2008 at 05:39 AM GMT
mfurman, my copy's sharpness is affected by the backfocus problem, I will get that sorted as soon as I got more time. I need my camera and lens right now so can't send them to kanon yet
And those test shots were not for sharpness, indoor lighting was poor and I had to shoot wideopen and crank ISO up to get desired speed.
Btw, shooting with this lens eats up my CF cards >_>, raw files come as 17-18MP on my 5D, any way to fix this?
Actually... let me clarify this... I see the same or similar specs at Canon's site for the 70-200mm F4 IS USM lens, but I don't see anything that says it can focus at the 1.2m figure when it's at 200mm... and I can't find a document that makes the claim of 1:5 magnification, etc... In general, what I'd really like to see is some really detailed data about this lens. I was looking for a nice detailed brochure, but the only nice detailed brochures of Canon's lenses I've seen don't include the 70-200mm F4 IS USM lens in them.
DynoMoHum wrote:
Those are not the specs for the 70-200mm F4 IS USM, and I can't find any specs that are that detailed about that lens at Canon's site. Not only that, even those specs do not say it can focus at 1.2m when it's at 200mm...
Edited by DynoMoHum on Feb 21, 2008 at 05:39 AM GMT
I seem to get pretty good results close to MFD (1.4m) at 200mm when shooting 3D objects. I noticed a slight back focus at f/4 at 1.4m/200mm. This back focus is not there when focusing from 3m and up. So when shooting flat test subjects at 1.4m-3m all looks out of focus. But take a look at this 100% crop taken at f5.6 at 1.4 FD/200mm (flash and IS on): REMOVED LINK
No PP and sharpening applied, seems pretty sharp to me
BTW I focused on the center of the key and the top is in perfect focus. Could either be the backfocus or the 5D's AF that seems to read more contrast at the top edge of the key.
Leon, I suspect your lens would benefit from calibration. Although, consedering the circumstances I find your pics to be sharp (you can count the little hairs).
mfurman, did you have your copy calibrated? It might do some good...
Edited by Daan B on Feb 28, 2008 at 03:47 PM GMT (Reason: removed link)
Daan B:
mfurman, did you have your copy calibrated? It might do some good...
As I said, I had two copies of this lens and tested them (together with the third one) quite intensively. They were all the same. I would then have to calibrate my body that is working perfectly with my prime lenses. The problem is that a zoom is never going to be perfect at all focal lengths and focusing distances (at least, I did not found one yet). Therefore, I decided to give up on using zooms all together. I have to admit though that my 70-200 f/4.0 L IS (that I had for almost a year) was very good in 100-155 mm range. That also means that unless I needed IS, I might just as well keep a 135 f/2.0 prime.
mfurman wrote:
As I said, I had two copies of this lens and tested them (together with the third one) quite intensively. They were all the same. I would then have to calibrate my body that is working perfectly with my prime lenses. The problem is that a zoom is never going to be perfect at all focal lengths and focusing distances (at least, I did not found one yet). Therefore, I decided to give up on using zooms all together. I have to admit though that my 70-200 f/4.0 L IS (that I had for almost a year) was very good in 100-155 mm range. That also means that unless I needed IS, I might just as well keep a 135 f/2.0 prime....Show more →
It a shame the 70-200mm 4IS didn't work out for you... I use the 135L as well and I am very pleased with it's IQ. I bought the 70-200 4IS mainly for travelling, but for payed portrait work the 135L is mounted to my 5D
Just to rule things out: on what camera body did you experience the MFD problems?
Daan B wrote:
I had a chat with Canon Service this morning. I explained the MFD issue to them. According to their specs, the MFD at 70mm is 1.2m and the MFD at 200mm is 3.9m!!! These are the tolerances that Canon finds acceptable.
EF 70-200mm f/4L USM
Closest Focusing Distance
1.2m / 3.9 ft.
It's interesting that the Canon tech quoted 1.2m and 3.9m, when the quoted specs state 1.2m or 3.9 feet. I wonder if he/she got mixed up with meters and feet?
I just checked mine under less than ideal circumstances and it beeps at just under 1.2m (about 1.18m from the centre of the camera body) at both 70mm and 200mm, and all the pics seem properly focused and very sharp.
Perhaps just a tad sharper at 70mm at 100% and 200% pixel peeping, but the aperture was f/4 and it wasn't on a tripod and very low shutter speed - so any slight movement would affect the longer end more than the shorter end.
I suspect the Canon tech was wrong about the quoted 3.9m MFD and the lens might not be working as it should.
It's interesting that the Canon tech quoted 1.2m and 3.9m, when the quoted specs state 1.2m or 3.9 feet. I wonder if he/she got mixed up with meters and feet?
I just checked mine under less than ideal circumstances and it beeps at just under 1.2m (about 1.18m from the centre of the camera body) at both 70mm and 200mm, and all the pics seem properly focused and very sharp.
Perhaps just a tad sharper at 70mm at 100% and 200% pixel peeping, but the aperture was f/4 and it wasn't on a tripod and very low shutter speed - so any slight movement would affect the longer end more than the shorter end.
I suspect the Canon tech was wrong about the quoted 3.9m MFD and the lens might not be working as it should.
Yeah, I also thought the tech maybe mixed up feet and meters... Anyway, I am still let Canon Service have a go at it. Here's what I think now:
My copy has a slight backfocus (probably over it's entire range). But, since it's a f/4 lens, the backfocus is covered up by the DOF. At least when focusing beyond 2 to 3 meters. Where the backfocus should be most visible is at MFD at 200mm since the DOF is very thin at that point. It also would explain why certain users have problems and others have not. There are also reports that things improved after calibration. If this doesn't work out I have an agreement with my retailer that I can swap this copy for another one.
, good luck and happy shooting.
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