Testing Sharpness of a lens yourself

[juana]

nkg,

I am have a Canon 24-70 2.8L. I love the color and the contrast and until now I was satisfied with it's sharpness. I read several message boards where folks were remarking about some bad build copies of this lens. This got me to examining every shot for sharpness until I am now doubting this fine lens.

Now the question:

Is there a target and a procedure that I can perform to verify that the lens is indeed as sharp as I think it is.

I am not pinching pennies so let me know what you think.

Thanks and Kind Regards,

Juana

[nkg]

Well, the Internet is full of people who complain and nitpick rather than go out and take photos.

I'd say - are you satisfied with the photos this lens takes? If you are, why do you care about bored online complainers? If you're not satisfied with the performance of the lens then maybe there's something to worry about.

You could tape a newspaper to a wall and shoot a bunch of photos of it and compare the results to other lenses if you really want to, of course. But the other lenses have to be shooting under identical conditions. (same lighting, camera on tripod, same camera settings, etc)

[juana]

NGK,

You make a lot of sense. I usually don't pay much attention to the complainers but I looking for another review on the Canon 24-70L after I came accross some poor ones. I found quite a few poor reviews on fred maranda's site talking about various copies being better than others which prompted me to ask the testing question. My life work has been a technical one and we find out why on a lot of things so it was natural for me to query about testing.

You are right! I do love the images I take with this beast and I think I will let it alone. It is always calming to hear from a peer.

Thanks

Juana

[nkg]

One thing to remember is that if you view a photograph on a computer at a 100% pixel level, even a really sharp one taken with the camera on a tripod, it will seem a little soft. This is a combination of the way most cameras record colour information, of the reality of optical design and so on.

But you're not normally viewing photos at 100% pixel magnification on a computer screen! You normally make prints of a certain size, or view images on a Web page or whatever. Viewing images at 100% is like using a powerful microscope to examine a slide.

I think a lot of the complaining from people about their lenses has to do with the way it's possible to view pixel-sized magnifications of images; something that wasn't possible in the film days.

I'm not saying there aren't some lenses with optical flaws out there. There are - but really, it's the proof of the final print or slide or computer image that matters.

[juana]

nkg,

You are on top of your game!

You stopped me from performing a study which is my craft, I am a Director in an engineering firm.

Photography is my escape from my work and I almost made it a project, PHEW! After I read your post, I took some frames of a reflective non planar object (my silver cel phone) here at my desk with several lenses at 70mm. I was impressed with the colors captured with the 24-70. I am sold and will leave it alone and enjoy the use of this lens.

Have a good one.

Juan