Focus Test Method

[sbuttrick]

I just got my D2x and am not really sure if my camera has a focusing problem. Part of the reason I'm not to sure what everyone means by back focus / front focus. All I know is that my images don't seem to be as sharp as I expected. I switched from an Olympus E-1 to the D2x with high hopes.

What would be the best method to test my camera / lenses. And what the heck is back focus / front focus Any help would be great.


Regards

 

[Phil K]

Hi Scott

You can try the focus chart method. Detail here :
http://md.co.za/d70/chart.html

Phil

 

[sbuttrick]

Thanks Phil,

I printed out the charts and will give it a try.

Thanks again,

 

[sbuttrick]

Phil,

Thanks for the info on focus testing. This is the results with my D2x with a Sigma 105mm at f2.8.

Subscribe to see EXIF info for this image (if available)

Looks like my camera is OK for focus issues.

 

[Beezle]

Re the softness...

I came from a D70 and a 20D to the D2X and for the first few thousand shots I had problems with that.

Once I came to grips with the fact that the D2X has twice the number of pixels that the D70 does on the same size sensor, I adjusted my technique as if I were shooting with longer lenses and it got better.

Smaller movements of the camera are needed to causing blurring.

And besides all that, I think the D2X just spits out slightly less sharp images unless you turn up (or even on - I have it set to none) in camera sharpening. I prefer to do that in post processing anyway.

I have some some that were perfect out of the camera, but that required a shorter lens, tripod, etc.

 

[DavidM]

Scott/Phil/Beezle -

The test chart you've used here is a good way to verify focus point for your camera/lens combination, but only under certain conditions -- usually with shorter lenses and with fixed targets.

Most people who have experienced focus acquisition issues with the D2x usually report that these issues are most prevalent with longer lenses (300mm+ in most cases) and usually with moving targets, neither of which apply to the above test. It's not always easy to replicate the right conditions to show these issues (it's hard to train birds to fly by at just the right time when you're ready). For that reason, there hasn't yet been an easy test that can conclusively show these issues on demand.

Essentially what it boils down to is this: use the camera. If you experience a substantially greater percentage of out-of-focus shots than can be explained by normal user errors, then try to document the issues and contact Nikon for assistance with a resolution. If you don't experience problems, then everything's cool! I wish there was a better way, but at present I don't know of one (and I really wish I did).

 

[sbuttrick]

Thanks everyone. I guess I just need more time behind the camera. I've been so darned busy at work there has been little time to use it.

 

[Chris101]

...

Most people who have experienced focus acquisition issues with the D2x usually report that these issues are most prevalent with longer lenses (300mm+ in most cases) and usually with moving targets, neither of which apply to the above test. It's not always easy to replicate the right conditions to show these issues (it's hard to train birds to fly by at just the right time when you're ready). For that reason, there hasn't yet been an easy test that can conclusively show these issues on demand.

....

After Jim F and others had discovered this problem, worrying about focus with the D2x increased. I believe this problem will really only crop up every now and then, there needs to be a simple test to discover if a particular D2x has the problem or not. Jim hasn't reported back on the focus of his replacement camera, so it looks like it is a problem only with specific cameras.

If I had a D2x (and a decent supertele), I'd try to develop a test using cars at an intersection a particular distance away. That way, you could image stationary targets, and moving targets at the same distance repeatably.

 

[DavidM]

After Jim F and others had discovered this problem, worrying about focus with the D2x increased. I believe this problem will really only crop up every now and then, there needs to be a simple test to discover if a particular D2x has the problem or not. Jim hasn't reported back on the focus of his replacement camera, so it looks like it is a problem only with specific cameras.

If I had a D2x (and a decent supertele), I'd try to develop a test using cars at an intersection a particular distance away. That way, you could image stationary targets, and moving targets at the same distance repeatably.

See this thread for why I believe I'm one of the few with this problem:

https://www.nikoncafe.com//forums/viewtopic.php?t=2463&highlight=

The problem I have with this is that it is very difficult to come up with a consistent set of criteria that make it happen, and the examples I have seen are not easily repeatable. While I guess it's not possible to know for sure, I'd still be willing to bet that the pictures in that thread would have been much better had I used the same lens combo on my D100 (based on my previous experiences).

I've got at least one trip (possibly two) coming up that I want to use the D2x on, but after that I plan to return the camera to Nikon for servicing.

 

[TexIndian]

Thanks for posting the link to the focus article, Phil.

I received my D2X Friday and it has been raining here since then....just my luck. I did slip out Saturday between thunderheads and snap a few shots with my 600mm with a TC on a heavy tripod and Wimberley head - a setup that has consistently produced razor sharp images with my D1X. I was really disappointed with the softness of the images - so soft that major efforts would be required to even approach what I'm used to getting.

But call it optimism or denial, I'm hoping for the best. I'll try this focus test and spend some time testing various lenses, etc. once the weather clears and I get the time. I'll let you know what my results are.