D200 backfocusing problem

[Rob-F]

Shortly after getting my D200 last year, I noticed it wasn't focusing fast manual focus lenses too accurately. I did the old "focus on the yardstick" trick and found the actual point of focus to be at a greater distance than indicated by the focus confirmation dot. I didn't do anything about it, just took note of it.

Last week I photographed a night-time sidewalk restaurant wide open with 50mm f/1.4 and f/1.8 MF Nikkor lenses. These scenes were back-focused. The light fixtures inside the restaurant were in focus, but the people on the sidewalk were not. I could not get acceptable shots until I stopped down to f/4 to let DOF take over.

I read someplace, probably last year on another forum, that the D200 focus confirmation feature is not accurate. I think they even said it back-focuses.

I have tested it with my two AF lenses as well. They do much better, but I am not sure if it might be because they are slower. My 20-35/2.8 shows no problem at all at 35/2.8. My 28-85 AF looks "pretty good" at 50mm, but at that focal length it is f4. DOF could be masking a problem.

I could, of course, try focusing to a closer distance, but it would be hard to know just how much closer to focus, and there may not be a handy target at that distance anyhow. Not much of a workaround!

Outside of shooting at wide apertures, I've had no problems. So: has anyone else run into this? Is it a built-in defect, or is it fixable?

 

[Todd.Hanz]

I have found the same issue on mine, it's hard to get an acceptable image at 1.2 on my 50/1.2, not impossible but you have to play with it. I wonder what the fix is if any?

Todd

 

[Nikon Bob]

Does the D200 have a fine focus tuning option in the menu?

Bob

 

[stompyq]

The D200 does NOT have a fine focus option

 

[stompyq]

Shortly after getting my D200 last year, I noticed it wasn't focusing fast manual focus lenses too accurately. I did the old "focus on the yardstick" trick and found the actual point of focus to be at a greater distance than indicated by the focus confirmation dot. I didn't do anything about it, just took note of it.

Last week I photographed a night-time sidewalk restaurant wide open with 50mm f/1.4 and f/1.8 MF Nikkor lenses. These scenes were back-focused. The light fixtures inside the restaurant were in focus, but the people on the sidewalk were not. I could not get acceptable shots until I stopped down to f/4 to let DOF take over.

I read someplace, probably last year on another forum, that the D200 focus confirmation feature is not accurate. I think they even said it back-focuses.

I have tested it with my two AF lenses as well. They do much better, but I am not sure if it might be because they are slower. My 20-35/2.8 shows no problem at all at 35/2.8. My 28-85 AF looks "pretty good" at 50mm, but at that focal length it is f4. DOF could be masking a problem.

I could, of course, try focusing to a closer distance, but it would be hard to know just how much closer to focus, and there may not be a handy target at that distance anyhow. Not much of a workaround!

Outside of shooting at wide apertures, I've had no problems. So: has anyone else run into this? Is it a built-in defect, or is it fixable?

Unfortunately i don't think the camera is the issue. I'am assuming your using nikons idiot green dot for focus confirmation. It's useless with any fast lenses and very inaccurate. For instance i couldn't get even 50% accuracy with my 105mm f/2.5 lens wide open but the same camera critically (and i mean that) focuses my 85mm f/1.4D when i'am using the center AF point.

If you insist on using MF nikors with your D200 you have two options. The best one is to install a Katzs eye screen with a old school split image. I have one on my D70 (which is x10 worse as the VF is even smaller) and have no issues with any MF lenses. The other option to perhaps ease your pain is to only use the center AF point (even when your on manual focus) active. This way the camera only uses the cross sensor. The other AF points are next to useless avoid them.

It's also possiable that your camera still has a back focus issue in which case you'll need to get a fast AF lens and do the focus test wideopen. Make sure you've confirmed that it itself isn't at fault (test it on another body).

Finally the only way to correct the camera (without a home DIY) is to send it to nikon melville. I would do that as a last option. The whole focus issue is overhyped. Your using a nikon not a canon😉

 

[Rob-F]

"Unfortunately i don't think the camera is the issue. "

"The whole focus issue is overhyped. "

"Your using a nikon not a canon😉"

Thanks, I followed everything except for the three lines quoted. 1) If the manual focus confirmation is inaccurate, why would the camera not be the issue?

2) Don't undestand why you say focus is overhyped. Focus is important, no?

3) Did you mean that Canon's DSLR manual focus is better than Nikon's?

TIA for clearing up those points.

Rob

 

[Rob-F]

OK, I was actually across the street, probably around 50 feet from the plane I thought I was focusing on. People seated six feet or so farther away looked a little sharper--not much--while things inside the restaurant, maybe another 12 t0 15 feet back, were definitely sharper.

I verified the problem by standing about 25 feet from some ornamental ironwork in front of my house, and then focusing first using the focus confirmation; then tweaking the lens to a closer setting in very small increments. The sharpest focus was obtained after 4 mini-tweaks closer.

 

[ZeissFan]

The problem with autofocus cameras and manual focus lenses is that it's difficult to rely on the autofocus light with any degree of accuracy.

Compounding this problem are the damn lines and sqaures for the various focus points, which get in the way of trying to manually focus a lens. Try focusing on someone's eyes when there's a black frame around the critical part.

Doubly compounding the problem is that the viewfinder screens (ironically also known as "focusing" screens) in these kind of cameras do not lend themselves to manually focusing a lens.

Adding a third element is the smaller viewfinders for some (although not all) of these cameras.

You combine all of these things, and you can see why it's difficult to focus accurately with an autofocus body. I have the same problem with a Pentax K10D and a manual focus f/1.4 50mm lens.

 

[stompyq]

Thanks, I followed everything except for the three lines quoted. 1) If the manual focus confirmation is inaccurate, why would the camera not be the issue?

2) Don't undestand why you say focus is overhyped. Focus is important, no?

3) Did you mean that Canon's DSLR manual focus is better than Nikon's?

TIA for clearing up those points.

Rob

😀😀😀

Sorry. Let me clarify

1) I personally don't know why this is the case. but it is a fact. I'am going to hazard a guess by saying that the camera has no way of knowing the exact distance the subject is since the lens is not relaying that information (the distance info) back to the camera. This is particularly true of old MF only nikkors (even the newer AIS lense) so in part the camera guesstimates and allows DOF to fill in the blanks. It works with regular lenses but not so much with fast glass wideopen. Especially when, even micro movements (by you) have a significant impact on critical focus. If your not convinced you should try the 85mm f/1.4D. That lens specifically has a learning curve (i bet it's worse on FX!!) for this reason. Newer AF lenses transmit distance info back so the camera can do a better job. Again this is only speculation on my part but like i said it is a fact of almost all nikons i've tried.

2) I'am a regular at FM forums and this issue comes up regularly. In most instances the camera is fine - although perhaps i shouldn't have made such a generalized statement!! sorry

3)🙂🙂 well to answer this question you should see the number of threads that moan about canon cameras AF accuracy. Again might be just that there are more canon shooters than nikon. But i generaly have found nikons quality control excellent


Sorry if i confused you. But like i said in my previous post the best option is a katzs eye if your going with old MF glass. I used to use quite a few of these with my D70 (katzs eye modeified) before getting rid of them to fund some 4x5 gear.

 

[Chris101]

Hiya Stompy,

The "D" function on modern AF Nikkors has nothing to do with autofocusing. It is there to help get the correct exposure with flash when used with Matrix metering. Newer lenses probably work better because they are in better condition, or because they use a different type of autofocus motor - the ones in the lens are called "AFS".

The focus point is determined by the contrast of lines passing through the focal point indicator (the selected rectangle in the viewfinder.) I don't know specifically about your D200, but on my D100 and D70, there is a set of adjusting screws for the focus, under the mirror. Gently lift it up, and you will see where the light for AF is redirected. If your camera consistently 'back focuses' (ie focuses behind the subject) then you will need to adjust those screws.

ps, points 2 and 3 I understand. I rarely focus at all, and the Canon IId Mark II (I think) had a severe focus problem when it was released which prompted a recall. Now everybody just assumes that Canon cameras all have focus problems.

 

[Rob-F]

@ stompya: thanks for the info. As for fast lenses being more of a problem, I have nothiced that the idiot dot stays on through a wider range of focus points with the 50/1.4 mounted, than is the case with the 50/1.8. Thus there is more ambiguity with the 50/1.4. I'm finding that the best focus can be best approached by turning the lens to the closest distance at which the idiot dot stays on.

@Chris: This sounds like it might be the cure, if mine has those adjustments.. I'll check it out! Thanks!

 

[Rob-F]

Hmm, the mirror does not seem to gently lift up, and I don't want to force it. I better wait and see if there are any comments/suggestions about that. I hope it really will be that simple and convenient to cure! I was about to ebay a couple lenses and grap some AF ones (I wonder if they will really autofocus better than the MF ones focus with the dot?).

 

[former member]

The mirror can be out of position, and that will cause problems. Just like when a rangefinder is out of calibration. I find it easier to calibrate the rangefinder when there is a problem.

As far as Nikon's AF-Confirm, it works well on my 10 year old E3 and 8 year old D1 DSLR's. And it works well on my N8008s. Have the camera checked.

 

[jonmanjiro]

I have a D200 and installed a Katzeye screen in it. Brilliant!

Before installing the screen I read that some people had front focus/back focus problems when using MF lenses on a D200 because the focus screen was not shimmed to the exact distance of the image plane from the lens mount (it doesn't matter with AF lenses because the focus sensors determine focus). Lucky for me my focus was spot on, but I've heard of people making their own shims from business cards etc. to get the height of the focus screen just right. The green focus confirmation light is basically useless for lenses faster than f2.8.

 

[Rob-F]

Okay, so where do I get this Katzeye screen? Is it a DIY installation?

Funny, my idiot light is white, not green. Say, maybe that's the problem. 😀

Funny, too, that the focus confirmation is least useful where you need it the most: with the fastest lenses. 😡

 

[willie_901]

There are shims between the focusing screen and the screen frame. It could be your camera does not have the proper shim installed.

The Katz-Eye screen works well. If you are good with mechanical repairs on small objects, you can do it yourself. You can also send your camera in to Katz-Eye.

Using the focus confirmation light with fast lenses may require some experimentation. The light may come on/off at different points when you move the focus ring CW or CCW. You may need to experiment with how your light comes on. The D200 has so many focus modes, it is possible some work selections better than others for manual focusing with the conformation light.

Like just about every DSLR I know of, the D200 designers and marketers assumed MF focus operation/confirmation was of no interest to practically all of their customers. They don't put scale useful focusing marks on any of their prime AF lenses either. This is one reason why modern digital cameras annoy me.

 

[Rob-F]

Question: Does the focus confirmation dot depend on the mirror position? Or does it work off the same system as the autofocus, independent of the mirror?

 

[jonmanjiro]

See http://www.katzeyeoptics.com/

Focus confirmation works off the AF system.

 

[Rob-F]

Thanks for the info and the link, Jon! I am guessing that the Katz Eye screen still allows autofocus, by centering the area of interest in the circle. Am I right so far? But probably does not support the use of focus areas not in the center, since they don't seem to be marked.

If the autofocus area controls were accidently moved away from the center, would there be any way to be aware of that, with the Katz Eye screen installed?

Thanks!

 

[jonmanjiro]

af works as before. there's no change to functionality.