17-55 lens critique

I decided to lighten my wallet a couple of bills, and picked up a few lenses. The first is a Canon 17-55 2.8. I should also mention that I'm a total noob at this thing called photography, so I'm seeking opinions on the quality of the lens I got. Is the blurriness (softness?) at 2.8, normal compared to the other stops?

All shot at approx. 16 inches from the subject, 35mm, ISO400, IS turned on, Av mode, focus on the top of the 'R'. No tripod yet, so it was propped up on some books, and I tried to not shake the table while pressing the shutter


1. 1/200, f2.8

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If these are 100% crops they look about right

Yes, these are my attempts at 100% crops

did you buy this fine lens to take shots from 16 inches away of whisky bottles? best to get a macro lens.

Martian, your crops look fine. EVERY lens is soft wide open, and gets progressively sharper as you stop the lens down (up to a point). What you are paying for when you look at the higher end lenses, is that they are less soft wide open than their cheaper counterparts.

Put a UV filter on the front of the lens and you won't have any dust problems. I've had a UV filter on mine from day one, and I have 0 specs of dust in the lens. The fault seems to be that the front element is not sealed very well, and allows dust to slide in.

BigBlueDodge wrote in post #3815930
Martian, your crops look fine. EVERY lens is soft wide open, and gets progressively sharper as you stop the lens down (up to a point). What you are paying for when you look at the higher end lenses, is that they are less soft wide open than their cheaper counterparts.

Put a UV filter on the front of the lens and you won't have any dust problems. I've had a UV filter on mine from day one, and I have 0 specs of dust in the lens. The fault seems to be that the front element is not sealed very well, and allows dust to slide in.

Yeah, the problem is with the gasket on the front end. Some crazy guy dismantled his and there were huge holes under the gasket. So if it isn't sealed properly, dust can get in. I have a filter on mine as well. The flare is awful (not sure how much is from the filter and how much is from the lens), but it is something I can live with.

To the OP, I agree with elader. Work on honing your technique in the real world, you should find this lens to be stupid sharp. No more pixel peeping, bad! Now, give me some whiskey!

i don't think you should have the IS on when it's on a tripod or sat still. It can actually cause image softness in some cases!

While the other posters are correct that the lens will be softer wide open, that really generally applies more to the corners and edges than to the center (Photozone's test shows the lens as being tack sharp in the center wide-open at anything other than 55mm focal length).

Your lens obviously gets sharper the more you stop it down. That may be due to the lens optics or it may be due to the focusing system. You can perform a test to determine which one it is. Get the focust test chart here: http://focustestchart.​com/focus21.pdf, print it out, and follow the instructions. Perform the test with your aperture wide open. If your lens is backfocusing or frontfocusing then you'll be able to see it with this.

It's entirely possible that your lens is fine, but with $1000 on the line, I'd want to be sure.

freakeystyley34 wrote in post #3816333
i don't think you should have the IS on when it's on a tripod or sat still. It can actually cause image softness in some cases!

that's only on the old versions of IS like that found on the 28-135. the new ones will detect that it's on a tripod.

Thanks for all the replys! I just want to convince myself that the lenses I recieved are the best they can be - so they can't be blamed for the bad shots I will inevitably make Nothing's worse than wondering if it's you, or your equipment. I also use the "protector filter" instead of a UV one...put it on as soon as I opened the package

I've read through the instructions on the web where the focus test is located. However, it doesn't mention the best zoom distance to use; wide, max zoom, or somewhere in the middle?

Also note that you could be altering the results from what the lens can do with that filter. This lens is very sharp and it takes an excellent quality filter to do as well as the lens can...(not that you don't have a good filter, I can't tell, just a thought to keep your results of the lens tests about the lens, not the filter) No system is better than its weakest link.

Thanks - hadn't thought of that. It's a Hoya Pro1 DMC Protector. Good? Bad? No difference?

*Martian wrote in post #3817508
Thanks - hadn't thought of that. It's a Hoya Pro1 DMC Protector. Good? Bad? No difference?

Good. That filter is a high-quality one, so I wouldn't expect it to make any real difference with respect to the sharpness of the lens.

So the next thing to do would be to do the focus test on that test chart I mentioned earlier...

Hope I did these right. Do I need to do this for various focal lengths? Or would something in the middle (ie: 35mm) suffice?

17mm (too dark?):

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*Martian wrote in post #3817775
Hope I did these right...

17mm (too dark?):

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35mm:

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55mm:

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Were these at f/2.8? They need to be as wide-open as possible. The depth of field on these seems a little large for f/2.8 to my (rather untrained) eye...

Also note that the depth of field depends on the distance between the camera and the focus point, and since you want to minimize the depth of field, that means moving in as close as possible while still showing the focus grid on both sides.

It looks to me like the lens+camera combination is frontfocusing slightly in the 55mm shot. Note how the scale at the focus target is a little blurry while the scale in front of it is clear. You can determine which one (camera or lens) is responsible for that by performing the same test on your other lenses. If they all consistently frontfocus then it's almost certainly your camera.

One more comment: be sure your horizontal location is as perpendicular to the paper as possible (while your vertical location is at 45 degrees). The reason is that you want to make sure that the focal point on the scales on either end are accurately measuring your focus field.