Inconsistent Focus

[david_love2]

<p>I have an old M645 (with 80mm 2:8 and 150mm 3:5 ) that was given to me. It seemed to work fine until just recently. I bought a different (brighter) focusing screen and all seemed well. Just recently, I have noticed that the film advance can be erratic, not advancing the film correctly. I have had a film with overlapping exposures. Most bothersome though is a very inconsistent focus on my negatives. Yesterday I did a test to try and eliminate if the focus issue was me. I loaded a film, and very, very carefully advanced the film. I was very deliberate and precise with my focusing. When I developed the film, my first exposure was not even there, the second exposure was only half there, and I experienced the focus (sharpness) inconsistency. Ironically, one shot was so in focus and sharp I couldn't believe it. In fact, none of my other shots to date with this camera have been so sharp! If only they were all this sharp. Anyway, my question is, could the film insert that is not advancing the film consistently also cause the focus problem. I do not have another insert to try but I assume that this is the problem. Any other thoughts?</p>

[bueh]

<blockquote>

<p>Any other thoughts?</p>

</blockquote>

<ul>

<li>Wrong type of insert (220 vs 120)</li>

<li>Insert's cogs/gear defective</li>

<li>Wrong focus screen (or wrongly inserted)</li>

<li>Film loading issues</li>

</ul>

[david_love2]

<p>Thanks for the suggestions...<br>

- It is the 120 insert<br>

- it is a focus screen specifically for the M645 and fits in with a little click<br>

- the film is being loaded correctly...at least the way I have loaded since I received the camera<br>

- I think you are correct about the cogs/gear issue..I forgot to mention earlier that the film advance has once had a jerk/drag to it when advancing the film (the time that the film has come out with overlapping exposures).<br>

I have ordered another insert, anticipating that this will correct the improper film advance/overlapping frame issue....and I am in hopes that some how this will correct the focus issue. I am thinking that if the film is not advancing properly, that it may also be not laying completely flat.</p>

<p> </p>

[marc_batters]

<p>I wonder if there isn't play in the magazine, not holding the insert tight to the back of the camera, not keeping the film precisely at the film plane?<br>

Like that one odd kitchen cabinet door that just won't stay closed against the cupboard, it always comes ajar.<br>

If there were play, the insert and/or the back could pull away from the film plane causing focus changes.<br>

Focus screen, you mentioned, pops in with a click. That's a constant. <br>

Your problem is intermittent, but worsening. That seems like mechanical wear.<br>

I hope your new/newer insert fixes the problem</p>

[david_love2]

<p>I thought about play in the magazine as well...I I have put just a little more tension in the tensioners on the inside of the door of the camera..hoping that this will put a little more pressure on the insert/magazine.<br>

I also agree that this is seeming like mechanical wear...looking forward to the replacement insert.<br>

One thing that I just learned (from reading the manual...go figure) is that the "start" line on the film must line up with the "start" line on the insert...otherwise one gets fewer frames...which may explain why the first frame was completely missing.<br>

Anyway, I have a portrait session tomorrow, so will give it a try again. Thanks again for the replies.</p>

[jmg1911]

<p>Have you checked the mirror and the mirror stop? If either has come adrift, focus will be erratic.<br />Just a thought.<br />JMG</p>

[david_love2]

<p>I have not checked that ...but I don't know how to check it. Can you instruct me? Now that the mirror has been mentioned, is it posible to do anything with it. It has a (discoloured and straight) line of crud buid-up or something that runs almost through the centre of the mirror.</p>

[neil_grant]

<p>Not sure what screen you have but I've never found the M 645 particularly easy to focus - especially with the 45 degree split image screen.</p>

[david_love2]

<p>Well, I think I have found the problem, although it seems strange. The only (tangible) variable that I have had is the new focusing screen, so I thought it couldn't hurt to put the original screen back in and shoot half a roll of film with the old screen and half the roll with the new screen. While putting my original focus screen back in the camera I noticed that, along the top edge of the screen compartment is a centre screw, and if I put a little pressure on either side of the screen, the screen will tip a little. It did this for both screens. When I developed the film, the images taken with the old screen were in focus, and the images with the new screen had some soft images... certainly can't understand why this is, but the old screen is back on the job (even though it is a little more difficult to use)..,any thoughts on why this would be...looking forward to any thoughts/suggestions.</p>

[david_love2]

<p>By the way...since I have loaded the film according to the manual (firmly rolling the film and lining up the film start mark with the insert start mark) I have had no problems with the amount of frames produced.</p>