Official: EF-S 15-85 mm f/3.5-5.6 IS USM

Question on Smaller Apertures

Folks,
I have a question on smaller apertures, if you can please help me out or enlighten me. I have had my 15-85 now for about 5 months and generally I am happy with the lens. When I take portrait photos of my family or subjects in fairly close distance (i.e. 6-8 feet away), the results are usually excellent (need to account for operator error here). And this is usually with apertures ranging from 5.6 - 9.0/10.0.

However, I am a little apprehensive of the results I get when I try to photograph landscapes with a smaller aperture to get a larger depth of field and get adequate sharpness. Once I start going past f/11, the photos do have more depth of field but are not as sharp as the closer portraits. For instance, using f/13 with a shutter speed of 1/125 (using Aperture Priority mode), and at 25-35mm focal length, the results will not be as sharp as when using f/9 or f/11 at at the same focal length. Now, I will say that I have not taken such shots with a tripod, but I figured the shutter speed was fast enough (1/125 or faster) that the image should still be fairly sharp.

Anyhow, I am hoping that folks can share some experiences with taking landscape photos at smaller apertures. I will try to post some examples at some point.

The other thing that I am suspecting is that I may be hitting the limits of the lens in terms of resolution given the distance (I am using a 60D by the way) and to see sharper images further away I will need a longer telephoto lens.

Kind regards,
Dimitri

DimitriNYC, you are hitting the diffraction limit of your camera's sensor. Any lens at f11 on your "cropped" sensor is going to lose sharpness at f11. For handheld shots, I would try to keep the shutter speed at 1/(2 x focal length x 1.6) or faster to reduce camera shake blur.

Most lenses will become less sharp as you stop down past f/8 or f/11. It is not very dramatic though so I suspect the softness you see is more to do with the subject matter rather than the aperture.

Another factor is atmospheric haze that is always present to some degree. Subjects farther away will always be more hazy than near subjects.

Why don't you do a test at various apertures to confirm it for yourself?

DimitriNYC wrote in post #14154882
Folks,
I have a question on smaller apertures, if you can please help me out or enlighten me. I have had my 15-85 now for about 5 months and generally I am happy with the lens. When I take portrait photos of my family or subjects in fairly close distance (i.e. 6-8 feet away), the results are usually excellent (need to account for operator error here). And this is usually with apertures ranging from 5.6 - 9.0/10.0.

However, I am a little apprehensive of the results I get when I try to photograph landscapes with a smaller aperture to get a larger depth of field and get adequate sharpness. Once I start going past f/11, the photos do have more depth of field but are not as sharp as the closer portraits. For instance, using f/13 with a shutter speed of 1/125 (using Aperture Priority mode), and at 25-35mm focal length, the results will not be as sharp as when using f/9 or f/11 at at the same focal length. Now, I will say that I have not taken such shots with a tripod, but I figured the shutter speed was fast enough (1/125 or faster) that the image should still be fairly sharp.

Anyhow, I am hoping that folks can share some experiences with taking landscape photos at smaller apertures. I will try to post some examples at some point.

The other thing that I am suspecting is that I may be hitting the limits of the lens in terms of resolution given the distance (I am using a 60D by the way) and to see sharper images further away I will need a longer telephoto lens.

Kind regards,
Dimitri

I agree with Bearmann that you're probably starting to get diffraction when you get up to F13 and more, although I have not noticed it until I get to f16 on m copy. At f11 it should still be fine.

My understanding is that diffraction occurs at smaller apertures when the amount of defracted light hitting the edge of the aperture blades is a much larger percentage of the total light getting to the sensor which is why as apertures get smaller and smaller with a greater DOF the image can actually get blurrier. Different lens start to show more pronounced effects of diffraction at different f-stops. While theoretically, the effect should get worse at any f-stop smaller than wide open, most variable aperture lenses seem to generate their best all around images at around f8.

Since the IS in the 15-85 is generally quite good to better than 3 stops, hand holding at 1/125 second should not be a problem at all. Perhaps you weren't holding the camera steady enough. Even with IS at that speed you still have to try to avoid too much camera shake. If you do use a tripod, turn IS off.

Folks,
many thanks for the quick turnaround on the replies. After going through the replies I am starting to think that what I am seeing is the lens' normal operation. I also tested the lens on the garage door (to check for softness in the corners) and it appears to perform well (again nothing scientific, but certainly helps me to better understand the lens' characteristics. I will try to get my act together to create a flickr account and upload some images.

Mike, as for the haze issue, I have noticed that, it took me some time to understand, but it does indeed affect the sharpness, even when fairly faint.

Can I ask if it possible to see your image of the roman waterway arch in a larger size? That is an amazing image. It reminded of our trip to Provence in 2007.

Kind regards,
Dimitri

msowsun wrote in post #14154957
Most lenses will become less sharp as you stop down past f/8 or f/11. It is not very dramatic though so I suspect the softness you see is more to do with the subject matter rather than the aperture.

Another factor is atmospheric haze that is always present to some degree. Subjects farther away will always be more hazy than near subjects.

Why don't you do a test at various apertures to confirm it for yourself?

I just can't take this lens off my 40D. There may be better but it works for me. I just shot this an hour ago a few miles from the house.

Ok, here is my feeble attempt at using Flickr. Feeble because I did not quite realize that to post full size images, I need a pro account with Flickr. Anyhow, I really appreciate the feedback and comments and advice, I think I am in good shape and the comments made more sense as I went back to look at the photos again. Here are the two images I discussed.

This is one is at f11

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

DimitriNYC wrote in post #14155805
Folks,
many thanks for the quick turnaround on the replies. After going through the replies I am starting to think that what I am seeing is the lens' normal operation. I also tested the lens on the garage door (to check for softness in the corners) and it appears to perform well (again nothing scientific, but certainly helps me to better understand the lens' characteristics. I will try to get my act together to create a flickr account and upload some images.

Mike, as for the haze issue, I have noticed that, it took me some time to understand, but it does indeed affect the sharpness, even when fairly faint.

Can I ask if it possible to see your image of the roman waterway arch in a larger size? That is an amazing image. It reminded of our trip to Provence in 2007.

Kind regards,
Dimitri

DimitriNYC wrote in post #14159686
Ok, here is my feeble attempt at using Flickr. Feeble because I did not quite realize that to post full size images, I need a pro account with Flickr. Anyhow, I really appreciate the feedback and comments and advice, I think I am in good shape and the comments made more sense as I went back to look at the photos again. Here are the two images I discussed.

This is one is at f11

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

IMG_0702_March 18, 2012_001 f11 by dimitrinikas, on Flickr

This one is at f8

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

IMG_0703_March 18, 2012_015 f8 by dimitrinikas, on Flickr

While there are some tonal differences between the two, when I blew them up, there was no difference in sharpness.

DimitriNYC wrote in post #14159686
Ok, here is my feeble attempt at using Flickr. Feeble because I did not quite realize that to post full size images, I need a pro account with Flickr. Anyhow, I really appreciate the feedback and comments and advice, I think I am in good shape and the comments made more sense as I went back to look at the photos again. Here are the two images I discussed.

This is one is at f11

IMG_0702_March 18, 2012_001 f11 by dimitrinikas, on Flickr

This one is at f8

IMG_0703_March 18, 2012_015 f8 by dimitrinikas, on Flickr

The larger f-stops will start to soften the image, but it won't be very visible unless you zoom in on fine detail - these are 100% crops, the left one shot at f/8, the middle at f/11, and the right at f/16. As you can see, the texture on the mousepad's surface starts getting a little less clear at f/11 compared to f/8, but not a whole lot of difference, but is clearly softer at f/16. These were shot using a 7D, where the aperture diffraction effect theoretically starts at about f/6.8. They're appropriate for this thread because they were shot using the 15-85.

Mark and stsva,
Many thanks for commenting and providing follow-up examples, to say I appreciate all this would be an understatement. I will also say that I can now sleep better at night and stop obsessing (no, really). I think the mousepad example really helped alot in this case.

By the way, on the images that I posted the processing consisted of the following:
1) Apply lens correction profile in LR3
2) Apply default parameters in the develop module, I did not move any of the sliders
3) I did not apply output sharpening either when exporting the images.

Now that I know the trick of how to upload (and now that I understand the results better), I will post a few more over time.

Kind regards,
Dimitri

stsva wrote in post #14162315
The larger f-stops will start to soften the image, but it won't be very visible unless you zoom in on fine detail - these are 100% crops, the left one shot at f/8, the middle at f/11, and the right at f/16. As you can see, the texture on the mousepad's surface starts getting a little less clear at f/11 compared to f/8, but not a whole lot of difference, but is clearly softer at f/16. These were shot using a 7D, where the aperture diffraction effect theoretically starts at about f/6.8. They're appropriate for this thread because they were shot using the 15-85.

I'm selling my Lens, so this will be my last picture taken with this lens..

I had to pull over on the side of the freeway to get this picture. I-5 Marysville, Wa

The water is actually a water treatment plant water storage, but it looks like a lake
A little blown out on part of the sky, but this is the best one I was able to get.

IMAGE LINK: http://imageshack.us …ges/818/mountai​nview.jpg/

Focus 'Hunting' with EF-S 15-85 mm f/3.5-5.6 IS USM

Searched forums, didn't find situ: Canon 40D, with thousands of shutter activations, and...
A month old Canon EF-S 15-85, USA lens which often has a symptom I would describe as 'focus hunt': at med-long focal length(s), using center spot focus, it will 'hunt' for focus on objects as close as ~10 ft and especially out toward near infinity on scene shots.

I often have to move/wiggle the camera around 'on the scene' to find a more distinct point to focus on; sometimes the 'focus hunt' is even a few seconds or more.

-If I slap on my old 17-85 Canon lens, (was giving me error 1 codes and was a dust magnet), it focuses in a split second...
-Same goes for my Canon 10-22 mm lens at all focal lengths, etc.

Have orig box and packaging and have not reg'd the lens yet. Lens seems sharp, good contrast, good focus, but it 'hunts focus' often.

Any ideas, comments or opins are welcome.
Best Regards, mD

I'm SERIOUSLY considering getting this lens as my travel lens. The last time I travelled, I found it a real pain to switch out my primes as needed, and given all the positive reviews I've read, I think this might be just what I'm looking for.

motordavid wrote in post #15219284
Searched forums, didn't find situ: Canon 40D, with thousands of shutter activations, and...
A month old Canon EF-S 15-85, USA lens which often has a symptom I would describe as 'focus hunt': at med-long focal length(s), using center spot focus, it will 'hunt' for focus on objects as close as ~10 ft and especially out toward near infinity on scene shots.

I often have to move/wiggle the camera around 'on the scene' to find a more distinct point to focus on; sometimes the 'focus hunt' is even a few seconds or more.

-If I slap on my old 17-85 Canon lens, (was giving me error 1 codes and was a dust magnet), it focuses in a split second...
-Same goes for my Canon 10-22 mm lens at all focal lengths, etc.

Have orig box and packaging and have not reg'd the lens yet. Lens seems sharp, good contrast, good focus, but it 'hunts focus' often.

Any ideas, comments or opins are welcome.
Best Regards, mD

Sorry to hear that. Mine never hunts unless its really very dark out. I've taken long night exposures with AF with no problems. Focus is instantaneous 99.9% of the time.I wish I could give you some advice.