Sharper Oranges

Now that the contre jour competition is over, I can ask a question about my submission.
David mentioned that the focus seemed soft in places, and I completely agree. I'd like some tips on how to make it better - I think I'm going to reshoot just to get it right.

Here's the set-up:
Professional light table (for viewing slides, etc)
mini-tripod, impossibly rigged to point the camera straight down
myself standing on the table to look thru the viewfinder
K100ds and 18-55mm kit lens
orange slices (duh)
EXIF:f/8, 50mm, 1/100sec, iso200, AF

Mac just mentioned that he uses this lens at f/8 with manual focus whenever possible. So my first thought is I should've tried manual?
(Giving serious thought to no longer letting my camera think for me all the time)

Anything else? And don't say "a bigger tripod" -- it's on my Christmas list!

If you're very close then the DOF is substantially less. So I would use f16 or even f22 to get everything sharp. The trade-off is that these may not be the best apertures in terms of quality, but on the other hand it's no use having things out of focus. In focus at slightly lower resolution will be better. I would use f16 if possible and I doubt that it will cause any problems other than camera shake from the slower shutter speed.

This is where a substantial tripod will make a difference. If the camera is not totally rigid then there will be shake. To minimise this I would use the 2 second delayed action.

A bigger tripod will help (the heavier they are the sturdier they are as a rule) but you can make the most of what you have by using a remote control and / or the timer function. The timer means that the camera is locking up the mirror before the shutter fires (reduces vibration) and a remote would mean you don't have to physically touch the camera (again reduces vibration).

Also don't be afraid to try a smaller aperture like f11 or f16 - it's a stationary subject and you don't need a lightning-quick exposure as you're using a tripod. While f8 is great for getting large depths of field at regular working distances it can often be too narrow when you're working very close to the subject.

While you're writing your Christmas list you might want to ask Santa for an angle finder too - save having to contort yourself to see what you're doing.

I really liked your original shot so good luck with Take 2.

John beat me to it once again...

Proof that great minds think alike! Are you two sure you're not the same person?

Thanks for the advice, very very helpful.

Legend has it we've never been seen in the same room...

I can definitely vouch for me not being the same person, so to speak...

Are we all convinced the focus is off? If the light was low I guess that the AF might struggle to use a fairly low contrast image to lock on but then the shutter wouldn't fire if it wasn't sure would it?

Did you shoot RAW and then post process?

If you shot RAW then try running it through SilkyPix and see how it looks if you fiddle with the sharpness.

I thought the image didn't look tack sharp (as they say) and I was planning something similar but switched to an apple after seeing your entry. Using a darkened room to avoid ambient light I used a flash off camera to illuminate the apple which meant I could use a very small aperture and the flash helped to freeze the image. getting focus was blue murder and I had to use a very bright torch to get a focus lock from the AF with the manual lens and then turn it off. I had the luxury of a very old but sturdy tripod.

Mike

If you turn off the option to use AF on half press of the shutter button you then have what Matt calls "AF on demand". AF is invoked by pressing the aptly named button on the back of the camera. In this setup the shutter will fire, even if focus is not confirmed in much the same way as if the switch on the front were set to MF.

For close up and macro shots on a tripod I would always use manual focus.

I agree and also make sure that your dioptre adjustment 'device' has been adjusted correctly as per the instructions in the manual (another JR tip).