Maxwell screen

[Nerobianchi]

Hi

I am new to LF having purchased a camera at the end of September 2011. I am really enjoying it but dawn shoots with a 90mm can be a little trying dire to the darkness of the screen. I have the opportunity to buy a second-hand Maxwell ultra bright screen. However, it appears to be designed for an ebony.

I use a chamonix 045-n2, does anyone know whether the screen would retro-fit my camera, and if so is it a difficult job.

thanks

[jeroldharter]

You will notice an improvement with the Maxwell screen. But they are sized for specific cameras. You really want a precise match. So unless the Chamonix is exactly the same size which seems doubtful, I would pass.

[Brian Ellis]

Unfortunately you don't say where you're located but if feasible I'd suggest calling Mr. Maxwell and asking him. Even if the screen you're considering doesn't fit your Chamonix he may be able to suggest some ways of making it fit. He's always been very helpful when I've spoken with him. He does go on a some length but I've always appreciated his interest, I'd much rather deal with someone who cares about his product and how it would work for the customer than some of the order takers who mostly want to get you off the phone so they can move on to other buyers.

[rfesk]

Bill Maxwell can cut it down for you if necessary.

[Leigh]

Bill Maxwell can cut it down for you if necessary.
... but he can't stretch it if necessary. :p

- Leigh

[Ivan J. Eberle]

The most difficult problem is when a replacement Fresnel screen has a different focus plane than the original. Provided you've got two screens with external dimensions that allow swapping in and out, if you can achieve focus with the GG and then exchange for the Fresnel without disturbing focus, you may be able to determine whether simply shimming it out (temporarily, with paper/cardboard) will be possible.

[rdenney]

The most difficult problem is when a replacement Fresnel screen has a different focus plane than the original. Provided you've got two screens with external dimensions that allow swapping in and out, if you can achieve focus with the GG and then exchange for the Fresnel without disturbing focus, you may be able to determine whether simply shimming it out (temporarily, with paper/cardboard) will be possible.

Most cameras put the focus surface towards the lens and the Fresnel behind it. In that case, nothing about the Fresnel will affect focusing accuracy.

Some cameras (the Speed and Crown Graphics among them) put the Fresnel between the focus surface and the lens. With these, the location of the ground glass must be adjusted to provide the same focus distance as the officially correct factory Fresnel arrangement.

So, the first thing to do is check the placement of the original Fresnel that has proven to function correctly. If it is mounted between the ground glass and the lens, a Maxwell screen will not drop in place without being appropriately shimmed (or modified). If the camera currently has no Fresnel, then the Maxwell screen will work fine if the external dimensions allow it to sit in the same place as the original focus screen. The focus surface of a Maxwell screen faces towards the lens, and the Fresnel treatment is on the back side of the screen, facing the user. There is a sheet of glass behind that to protect the polymer screen.

So, given no mention of a Fresnel on the original camera, I suspect it's a matter of whether the screen fits in the opening where sits the original ground glass.

Rick "knowing that some Chamonix cameras have had ground glass adjustment issues, but not remembering what they were" Denney