50mm f/1.8 AF Focus problem on D90

<p>I've been finding it hard to get sharp portraits with my old 50mm AF lens (pre-D version). I loved this lens on my F801s, but results have been very disappointing on the D90.<br>

I tried a quick test this afternoon shooting a tape measure, and it appears to be forward focussing significantly (approx an inch forward from 1m distance at 45 degrees). The 18-105 kit lens seems fine in the same test.<br>

So my question is what can I do? I suspect it would be cheaper to replace than repair.</p>

<p>Thanks<br>

Chris</p>

<p>You can send both the camera and lens to Nikon and have them determine what the problem is. Although the estimate is free and there is no obligation, I suspect that you are correct in that a new 50mm f1.8 lens costing about $125 would be less expensive than even the simplest of repairs.</p>

<p>As I am someone that doesn't have years and years of experience would something like this really be such a big deal. It would seem to me that one could easily correct what they are doing while taking a shot if they knew this to be true all the time. I'm thinking by adjusting your aperture you could eliminate this.<br>

Yes/No ....... This is interesting to me. <br>

Also I have no idea on how to conduct a test to see if my lenses are dead on?<br>

phil b<br>

benton, ky</p>

<p>Thanks guys.<br>

Phil, you basically do something like this: <a href="../learn/focustest/">http://www.photo.net/learn/focustest/</a><br>

My test wasn't so scientific. Before I do anything else I'm going to do it properly. I'm still not convinced it isn't my technique. Don't want to spend money only to find out its me!</p>

<p>It became very noticable when I was trying to use a very shallow DOF creatively this afternoon. Just couldn't get the eye in focus. For me, the main value of the 50mm (over the kit lens) is the shallow DOF achieveable and its low light capability, so it would rather defeat the purpose of having the lens if I had to use a smaller aperture to achieve focus.</p>

<p>I was wondering whether anyone else had experienced similar problems with older full frame AF lenses. My lens is 20 years old and has sat unused in the loft for most of those.</p>

<p>Chris </p>

 

<p>Sounds like it's just the difference between body "screwdriver" focusing and lensmotor focusing. Does the lens feel stiff or sticky to focus manually? If so the lens probably needs a service. But doesn't the D90 have an AF fine tune option?</p>

<p>OK. Have now taken the time to do the test properly; and the forward focusing is not that bad....</p>

<p>This is the result</p>

<p>Try again...</p>

<p>Then I took this........</p><div></div>

<p>and this.....</p><div></div>

<p>I are playing around with different apertures with this lens. This one picture right above seems to be very shallow dof im guessing your pretty wide open. I have the D90 and 50mm 1.8d and wide open to almost around 2.8 its soft but above that its pretty sharp.</p>

<p>Bjorn, both were taken at f/1.8.</p>

<p>The second portrait was taken at roughly the minimum focus distance, so the DOF is very shallow. I'm pretty satisfied with the sharpness wide open considering the lens is 20 years old.</p>

<p>I can see slight forward focusing in the tests, but I've concluded that the problem is/was mostly technique (probably me focusing on the eyebrows or nose).</p>

<p>Feel a bit of a idiot posting on here; but hey, I don't have to buy a new lens ! :-) </p>

<p>I am testing my new Nikor 50mm 1,8 D (made in China) with my D90 (all brand new with less than 100 photos)</p>

<p>I am disappointed, but maybe I am doing something wrong.</p>

<p>The images taken with the 50mm are worst than the ones taken with the 18-105mm DX zoom (at 70mm and with the same aperture), thats was unexpected.</p>

<p>Below is the comparison.</p>

<p>I can see two problems, one is that the autofucus do not work perfectly with the 50mm lens (I improved the takes using it in manual), the another is the lack of «clarity » you can see it in the marked zones.</p>

<p>The only advantage is that it allows a higher speed, thats all.</p>

<p>Do you have any idea about what can be happening? </p>

<p> </p><div></div>

<p>Problem solved, in fact there was no problem.<br>

It was the the VR what allows the zoom to work better than the 50mm.<br>

So, I am more impressed with the VR than with the 50mm, that works ok.</p>

<p>Cool shots and thanks again!</p><div></div>