Putting back together a 500c focusing screen

[daniel_vignal]

<p>Hello,<br>

I had the brilliant idea of taking apart a standard 500c (non interchangeable) focusing screen to clean. A drop of sweat had gotten in between the two plates and had dried leaving a residue. <br>

I took the screen apart and proceeded to clean it with Pancro lens cleaner and lens tissue (brilliant idea #2). I of course took off most of the guide marks on the glass. Fortunately this was a standard focusing screen and not an acute matte or anything fancy.<br>

I tried putting it back together but can't seem to get the order right. Should the engraved concentric circles be at the bottom (facing the prism)? and should the frosted side (top plate) be facing the top or bottom?<br>

Any help would be greatly appreciated. I searched the forum and couldn't find any conclusive answers.<br>

Thanks,</p>

[daniel_vignal]

<p>Sorry, after searching some more I found the answer.<br>

However, I still don't know how to recalibrate focus. Any insights? </p>

[Aoresteen]

<p>DIY alignment at home is very hard. If you have the ground glass adapter and a 2.5x loupe you can do it by trial and error and a lot of patience.<br>

It's best done using a collimator. My advice is to send it to a competent Hasselblad technician and let him set it to factory specs. Contact David Odess at</p>

<p>http://www.david-odess.com/</p>

<p>David is active on this site so he may comment here. He's done work for me a lots of other members and he is highly recommended.</p>

<p>I have a Maxwell screen in my 500C. It's well worth it to have one put into you 500c. Call Bill Maxwell at (404) 244-0095 for info on his screen. He just did a screen for my Mamiya M645 and it's fantastic.</p>

 

[tom_chow]

<p>Hasselblad has a special calibration tool/jig to set the focus screen on the "c"s.</p>

<p>The home hack is to use a lens that you know has a proper infinity focus. Set up the camera to focus at infinity on some distant object, and adjust the 4 screws holding the screen until it is in focus at the center, and at the 4 corners. This usually gets you close enough for film.</p>

[douglas_fairbank]

<p>Fresnel lens goes in first with the rings facing up, then the glass with the ground glass facing down. You can only get the calibration perfect using factory tools but try to have all the screws at the same height and use a loupe and known good lens to calibrate. That distant object people talk about should be a mile away!</p>