Sharp close-up focus. Help!

Cinka · Sep 28, 2008

Issue: Sharp close-up focus

I'm shooting close up product (shoes with rhinestones) and no matter what I try, I can't get the focus completely sharp. This is particularly noticeable in the rhinestones, which are small and multi-faceted.

I'm using a Canon 40D and a Canon EF 24-105 f/4L IS lens, a light-box, two lamps, and a speedlite. AF is turned off. Mirror lock is on. I'm using a tripod and have tried 2-10 seconds timer to minimize vibration. I'm running out of ideas. The depth of field is shallow, but there doesn't seem to be ANY spot that's in focus.

Is the 24-105 lens able to shoot sharp close-up details? I can get reasonably sharp results when I'm in macro, but that's too close for the product. The lens' minimum non-macro distance is 18 inches. Even at 24 inches, I still get soft details.

Help?

Shutter: 0.3s
Aperture: f22

Thanks in advance for your help!

potownrob · Sep 28, 2008

I would try a bigger aperture to get things sharp. At f/22 just about everything's in focus but nothing's sharp. F/4 should be sharp despite being the biggest aperture but I'd try something between f/5.6 and f/8 since it would probably look sharper. Another benefit of the bigger aperture is quicker shutter speed which means less chance of camera shake.

Flash Harry · Sep 28, 2008

if your using it (IS) try turning it off and I'd also go f8-f11-f16 and view the results to determine the sweet spot on the lens, also focus 1/3 into the image/shoes. H

manaheim · Sep 28, 2008

+1 to everything they said.

Also be aware of the minimum focusing distance on your lens. Look on the bottom and it will tell you "infinity to XXX". Whatever XXX is, is the closest you should get to your subject. (you being the end of your lens)

davebmck · Sep 28, 2008

Sometimes you can get better results by moving the camera away form the subject and zooming in. That will improve your DOF as well. I agree with the above that you should use F8 to F11.

Cinka · Sep 28, 2008

Thanks guys! You all rock. Will definitely try your suggestions today and post results.

I wonder, is there a lens that can get crisp close-ups of items with rhinestones at f22? I was hoping to catch that sparkle effect you get with a smaller aperture. Might have to face facts that it's all about post processing.

JerryPH · Sep 28, 2008

Every lens does have a sweetspot. Knowing what your lens' sweetspot is, will result in better pics.

For most lenses it is 1 particular aperture somewhere between F/5.6 and F/11. For example, on my 50mm F/1.8 lens, it's sweet spot is F/7.1, on my 18-200 Nikkor, its F/11.

Find out what the sweetspot is for your lens... and use it!

Cinka · Sep 28, 2008

OK, so I tried f4 through f11 and at one point, determined that f11 at 1/160 was pretty good, not brilliant, but much better. I was zoomed in. When I went back to shoot the whole shoe, no dice. Still the same results as before. I can't seem to find the "sweet spot" - I've tried all combination of shutter speed and aperture.

Perhaps this is a limitation of the sensor of the 40D or is is possible that the lightbox is causing the rhinestones to haze or become fuzzy?

Thanks!

Joves · Sep 28, 2008

Maybe it is the lens and not the limitation of the sensor. What other lenses do you have to play with? You might try one of those and see what the results are. Especially if you have a prime.

davebmck · Sep 28, 2008

I agree with Joves. What lens are you using? That's what I would be suspicious of at this point. Your 40D is capable of capturing perfectly sharp images.

Cinka · Sep 28, 2008

My lens is: Canon EF 24-105 f/4L IS lens - I also have a 50mm macro 2.5. I also tried the 55mm standard that came with my Rebel XT. Same results every time. It appears all 3 lenses are getting the same results. Which is why I'm starting to wonder if it's not light refraction or bounce or something to do with the lightbox. Who knows. I'm stumped.

It's very odd. I just tried letting the AF do the work, thinking maybe my eyesight ain't what it used to be -- even locked the AF. Same. Still fuzzy and not sharp.

Joves · Sep 28, 2008

Well in manual you could measure your distance with a tape measure to the focal plane. If that body has it marked. I know it is the old fashioned way but it works.

Poaceae · Sep 29, 2008

Joves said:
Well in manual you could measure your distance with a tape measure to the focal plane. If that body has it marked. I know it is the old fashioned way but it works.

Measurement really works and remember that the measurement is not to your lens but to the line in the circle shown on the top of the camera near the diopter ajustment dial.

Mike_E · Sep 29, 2008

When was the last time you dusted off your sensor?

Bifurcator · Sep 29, 2008

Joves said:
Maybe it is the lens and not the limitation of the sensor. What other lenses do you have to play with? You might try one of those and see what the results are. Especially if you have a prime.

Yep, that's definitely something focus or lens based. That's way too bad to be a sensor problem unless you have a 2-years-old that slobbered in the thing or something.