Newbie seeking DOF advice

After much searching on the internet, I thought my understanding concerning depth of field and the required settings for my camera were adequate. Unfortunately, the photos I'm taking are still lacking both in depth of field and sharpness. Here are a couple of photos using an 8 MP Canon Rebel XT and the included lens (18-55mm) set to 18. The camera was set to aperture priority mode (f-16). The model is 12 inches away from the lens front and fluorescent lighting was used. I used the camera's setting for this type of lighting. Camera shake was eliminated by using the timer and a tripod. The first photo was taken using f-16 and the last one at f-22. Any advice or suggestions are appreciated. It appears my images get grainer with the increase from f-16 to f-22. My problem may be the limitation of the lens used. Would switching to a wide-angle lens improve my depth of field while providing sharp images?

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/1.JPG

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/F22_3.JPG

The second one just looks out of focus. You might try it again with manual focus.

I think Bruce_B is right, the f22 shot is not focussed correctly.
I wouldnt expect to see any difference in this setup between f16 and f22.
the f16 shot appears to have sufficient depth of field to cover the entire subject.
All lenses have a sweet spot where they operate to their highest optical quality and this is rarely at the extreme ends of the apature range, the edges of the glass or in the case of zooms at either end of the range, so you will see a change in image quality as you push the lens towards it limits. Especially the kit 18-55mm which is not great to start with.

Oh and dont forget that Flourescent lighting has it's limitations in photography as it does not provide a constant output level.

Explanaition here: https://photography-on-the.net/forum/showthre​ad.php?p=790596

The f22 shot is darker and digital sensors become prone to noise as the available light level decreases

Could it be that the model is just a bit close?

The close focus on this lens is 1 .15'

If you have studied up on DOF you might want to check into lens diffraction. Here is a good technical link.

http://www.cambridgein​colour.com …ffraction-photography.htm

never mind...Welcome aboard.

id try move camera farther back and move the setup closer to a window so u can have some sunlight coming in. I think one foot is too close to get nuff dof.

I used the lowest ISO possible (100) on the camera when taking the earlier pictures. For the next pic, I changed the light setting for the camera from fluorescent to Tungsten and changed the actual lighting as well. Staying at f-16, I used manual focus to take 11 pictures of another model. Starting at the business end of the barrel, I focused on a different part of the model in each picture working my way back 1 inch at a time. Using a trial version of "Helicon Focus" I then combined all 11 images producing one image with the entire model in focus. Here are the results.

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/T90upload.jp​g

While this appears to work, Taking 11+ pics for one usable image is a minor pain. With the Canon Rebel XT, does anyone have a recommendation for the best additional lens for model photography?

came out great! just the front part is a tad soft but 11 shots!! thats alotta work!!
and for model/close up work, u have to buy a "macro" lens!! also extention tubes are a nice addition for really getting close ups.

ALWeller wrote in post #5878558
I used the lowest ISO possible (100) on the camera when taking the earlier pictures. For the next pic, I changed the light setting for the camera from fluorescent to Tungsten and changed the actual lighting as well. Staying at f-16, I used manual focus to take 11 pictures of another model. Starting at the business end of the barrel, I focused on a different part of the model in each picture working my way back 1 inch at a time. Using a trial version of "Helicon Focus" I then combined all 11 images producing one image with the entire model in focus. Here are the results.

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/T90upload.jp​g

While this appears to work, Taking 11+ pics for one usable image is a minor pain. With the Canon Rebel XT, does anyone have a recommendation for the best additional lens for model photography?

Al, first of all I applaud your patience and enthusiasm at taking all those pics just for one shot!

Generally as I understand it, there isn't often much point in pushing your f/stop above 16, especially not for close in work. I think i may have even used a larger aperture of around 11, which would have allowed you to keep the iso low without worrying about exposure etc.

The light certainly is an issue. The first two shots are taken in horrible lighting with a poor white balance. The third is better but as you've stated, glueing together 11 shots is time consuming and has led to odd shadows.

My Macro lens is the Sigma 70-300mm DG. It was under £100 ($200) and is a nice lens. I would certainly consider somthing similar.

My final suggestion (and you can throw all of these away lol) would be a ring flash of sorts. There is a £100 one on the market which would solve your lighting issues.

Nik.

Another thing you can try is leave your lens at 18 and back away from the subject. This will increase the DOF. Your subject will be smaller but you can crop it and see if it works for you. I'd try different distances to find the best trade off between DOF and subject size.

Have you checked the DOF calculator? It will let you figure the DOF you will get with a given group of settings.

As beatnut said, the white balance is off. Thats the first thing I'd fix, makes everything else just look off.

Thanks for all of the great info. I have used an 18% gray card to set a custom white balance, changed the background and backed off the subject. The DOF calculator was quite handy, thanks. While lighting remains a challenge, here are some early results.

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/Front.jpg

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/rightrear.jp​g

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/overhead.jpg

(URL: Blacklisted URL removed)http://img.villagephot​os.com/p/2008-1/1294664/leftside.jpg

1000x times better, good job