Opinions on a "Focus Issue" - D200

[OutLore]

:help:Hi all,

Opinions please!!! This is kinda long so if you stick with it - THANKS!!!

I recently started to notice that some of my shots from the D200 were not as sharp as I would have expected. Presuming it was my technique, I started to try all kinds of things - faster shutter speeds, using a tripod all the time... The only way I could actually get any kind of sharpness was to stop it right down to F16 or lower.

I got a focus test chart from Tim Jackson's site (CLICKY) (http://focustestchart.com/chart.html) and started to shoot as described, finding that depending on the focal length used, my focus was between 4mm and 10mm behind where I thought it should be.

So I set everything up, used the D200 and the D40, both with an 18-200 and 55-200 lens - and the results can be seen at the link below.

D200 vs. D40 Focus Test (http://www.tiddtech.co.uk/D200Focus/page.html)

The same settings were used (apart from WB as you'll see :bang: but I think they show the D200 as having 4-10mm of back focus.

Before I send it in to be checked - any opinions? Something I am doing wrong?

I gave both cameras a factory reset before the test, the only thing that I changed after that was the WB on the D200 and to make them both shoot in RAW. Both lenses had their filters removed, ISO was a constant 200, both cameras on a sturdy tripod and a remote shutter release was used for both cameras.

No processing aside from resizing, JPEG'ing (at 100%) and cropping has been done on any of the images - resulting in a 100% crop.

Both

:help:

[Chappers]

The only flaw I can see with this test is that it works at very close distances. You may be better off trying it at a distance more appropriate to the distances you normally use the camera. The closeness of the chart may be inducing errors. If you can repeat the test using a different test target it may help.

Try shooting a brick wall, preferably one with a textured brick surface, at an angle. Mark the wall with a focus point and then when you evaluate the image see if the area at the mark is sharp or has the focus shifted. . Also if you can try focusing manually, and see if this makes a difference.

I did something similar when I thought I had a focus problem with my canon 100-400. It turned out the focus was locking onto detail near the subject ( blades of grass), not the subject itself, since then I've changed my technique, and all seems fine

[OutLore]

The only flaw I can see with this test is that it works at very close distances. You may be better off trying it at a distance more appropriate to the distances you normally use the camera. The closeness of the chart may be inducing errors. If you can repeat the test using a different test target it may help.

Try shooting a brick wall, preferably one with a textured brick surface, at an angle. Mark the wall with a focus point and then when you evaluate the image see if the area at the mark is sharp or has the focus shifted. . Also if you can try focusing manually, and see if this makes a difference.

I did something similar when I thought I had a focus problem with my canon 100-400. It turned out the focus was locking onto detail near the subject ( blades of grass), not the subject itself, since then I've changed my technique, and all seems fine


The test runs from around 0.75 - 1m (or at least that's what I did) so I think this is quite a normal distance to be taking shots at... :shrug:

However the thing here is not really the test I am pointing out - more the difference between the D40 (which seems fine) and the D200 (which doesn't):D

As I said, I have tried pretty much everything I can think of to get sharper pics - from all different lengths, they just all seem that little bit out of focus!! Even if I take a pic of a goose at about 10m away, nothing on the bird itself is in focus, but the water just behind it seems to be - I tend to use a single focus point rather than letting the camera decide which one to use, so I know that my selection may be off!!

The D200 has to go in to have some warranty work done anyway (Single frame shooting mode isn't single frame, it's multiple frame high) so I might just see if they can calibrate it while they have it....

Your test seems to make sense - I'll have a go at setting something up later or tomorrow if I can...

Any other opinions?:shrug:

[Chappers]

As it has to go away then it makes sense to get it checked out.

Hope it comes back OK, nothing like having a camera/lens you don't trust

[OutLore]

As it has to go away then it makes sense to get it checked out.

Hope it comes back OK, nothing like having a camera/lens you don't trust

Tell me about it - been out today and all I can think is "it probably won't be in focus but I'll take the shot anyway" - then I have Mrs.Outlore with the D40 taking nice sharp shots....:razz:

[Dogfish_magnet]

I think for that test to work correctly you need to have the aperture set to the lowest value possible, f2.8 or less if possible - this should give you about one line of text in focus only, the line you are focusing on, so if you have a back focus problem another line will be in focus only.

[OutLore]

I think for that test to work correctly you need to have the aperture set to the lowest value possible, f2.8 or less if possible - this should give you about one line of text in focus only, the line you are focusing on, so if you have a back focus problem another line will be in focus only.
That's exactly how it's supposed to work - however you have to use the lens's max aperture, regardless of what it is.

If you look at the pics - the centre line where focus is supposed to be on the D200 is slightly off and the D40 seems perfect.... The line which is actually in focus on the D200 depends on the focal length used - but is between 4-10mm back from the centre line