D40 back focus

[ishi_p]

 

Hi. I seem to having problems with my d40. I got get it recently (used) and a 50mm 1.8D to go with it. I know it's manual focus and not the ideal screen but i noticed from the start it was back focusing, even after replacing my focus screen with a split image one, the issue remains. Without paying to much attention to the green spot (which has lots of 'in focus' travel) the images LOOK in focus on the screen, on both screens. <br /><br />

I could understand it being a lens issue if i was using auto focus, But to look on the screen and actually be having to un-focus the area i want in focus seems to point to the camera. <br /><br />

The lens I got was boxed and seemed hardly used. But I will add that the barrel seemed to be somehow loose inside so when using manual focus the image judders a touch when you turn the focusing ring from one direction to the other. This did lead me to suspect that when the camera actually fires it puts the lens out of focus. But i would assume it would be something that would show up in an inconsistent manner if it was, Ie sometimes back and sometimes front.

 

 

As it happens focus does seem better when I come from closer distance, rather than focusing from infinity backwards when i'm using the green dot. But when using the split image (and with the original screen) i'm funding the two don't correspond.

<br />

Is Manual focus just a lost cause on this maybe? It seems a shame because I do like this camera, but i don't know if i want to put up with this issue.

<br />

I have been learning about and successfully restoring film cameras for some years now and am also wondering if somehow adjusting this is possible without specialist equipment, I will obviously also be doing some research on this myself.

<br />Thanks in advance.

 

 

[epp_b]

<p>The small viewfinder in the D40 is not large or accurate enough for manual focus on fast lenses like the 50/1.8.</p>

<p>I use a 50/1.8 Series E (manual focus) on my D40 and I have no problem trusting the green dot.</p>

[ishi_p]

 

 

<p>Yay. I got front focus, It makes such a refeshing change. After reading up i decided it was ether shims of adjust front hex screw. I'm not into shims so decided on the latter. It does not need much of a turn to pull the focus back. I went a bit far but it's pretty close now. Ill wait to get a new hex tool first as the one i have is poorly made and does not fit so good. <br>

I did read that differing views about what these hex adjusters do. but the front one does change the view of what you get in focus.<br>

I don't know yet if this is tied to the green dot, i will have to check, but before there was a large travel of focus where the green dot was on. And the sharpest area of focus was not near the middle of where it went on and off. No way near in fact. <br>

I assume these are just not well calibrated for manual focus. Or mine was not. <br>

I like to shoot a lot of wide open shots and it has been back focused so many times. It will be lovely to have it working good again. I may even put the original screen back if I do now find the dot to be better. </p>

 

[ishi_p]

<p>Well, just doing a few test shots it does seem the dot is much better. I could guarantee before that if I got the dot totally solid and more of less in the middle of being on it would back focus. Now it seems better.</p>

[ramon_v__california_]

<p>i think the only time a camera will be guilty of back (or front) focusing is if the focus screen is not seating in place properly.</p>

<p>why don't you use the green dot as a benchmark and test the two focus screens. then you dump the one not matching the green dot's results :-) .................or adjust to your satisfaction ------- you might need to shim the split-image screen.</p>

<p> </p>

[ishi_p]

<p>I did re-seat the original screen when I got it and before and after was the same. Having read so much on this issue i hardly think it is the focus screen not being seated properly. It would make it miles out because there is only one lip it could possible be caught on. In fact I don't think you could close the latch if it was not in correct, its a pretty simple housing for it.</p>

<p> </p>

[ishi_p]

<p>So while i'm here I may as well do a report on the screen. It's one from china, It seems good, no noticeable effect on exposure using center weighted, though the center is a large clear area vs the rest of the screen.<br /> <br /><br /> The matte part of the screen is pretty dim, and king of fuzzy. It blurs the image to some extent, not the same as good quality matte screens. It may be ok in good light, but not so good for low light.<br /> <br /><br /> The 45%, ;) split area is good (as is the surrounding micro-prism) though they are big vs a film camera with this view. So this could be an issue. But on the whole I think it's good so far, for me it was worth it for the tweezers (2 of) And they are acutely nice tweezers, as a repair guy as well i appreciate that kind of thing.<br /> <br /><br /> I may upgrade to a katzeye at some time, but for now it does a pretty good job. <br /> <br /><br /> I know it's slightly masochistic but I find there are still some benefits to manual focus. Maybe it's just the stillness.<br /> I can see myself enduring more punishment when I get my own E 50mm. It's gonna be harder than B&W film to guess, but i'm up for it.</p>

[matt_smith24]

<p>If the camera is front or back focusing in manual mode it ususally means that the angle of the primary mirror needs adjusting. As you've found you can do this by adjusting the front hex screw in the mirror chamber. If the AF is front or back focusing it usually means the that the angle of the secondary mirror needs adjusting - the rear hex screw is adjusted for this.</p>

<p> </p>