Keep us posted how the Hopf screen works on the Ebony..I have the RW45 but was not aware of the need of a camera back modification needed when using the ebony.
Keep us posted how the Hopf screen works on the Ebony..I have the RW45 but was not aware of the need of a camera back modification needed when using the ebony.
Yes...I was referring to your post. I have been in contact will maxwell and I will ask him directly if there is a modification needed on my Ebony. Unfortunately it will be in a couple of weeks till I get back in town since Im on the road working at this time. Anyways Im just curious how the Hopf screen works out for you.
I will let you know - it should arrive in a couple of weeks.
The Hopf screen arrived a few days ago and I installed it just this morning. It is not brighter than the original (I knew that would be the case) but the markings for the roll film formats are an improvement for my eyes: more pronounced, heavier lines. It looks well made and dealing with Steve was a pleasure as well.
The Hopf is easier on the wallet compared to the Maxwell but the Maxwell screen is probably two stops brighter.
4x5 Maxwell screens are generally "all in one." That is, they consist of a single piece, incorporating a fresnel field on one side and a frosted ("ground") surface on the other. Cameras need no modification with this 4x5 screen, so long as the frosted side is mounted toward the lens. Bill Maxwell would then recommend that you place a protective glass over the rear of this, as the fresnel field is a bit sensitive to scratches.
For 5x7 and larger, Bill Maxwell no longer manufactures such "all in one" screens, but rather can supply a "kit" consisting of a fresnel screen and a ground glass, which the user then installs. (Bill might install also, but don't quote me on this). At any rate, choosing to install the separate fresnel in front (on the lens side) of the ground glass (preferably with the fresnel field facing rearward) does indeed require that the ground glass frame be modified, to adjust its depth to accommodate the assembly, both physically and optically. Bill can give you the exact formula for this if you want to tackle it yourself, as I did with my 5x7.
If, however, you choose to mount the separate fresnel field behind your ground glass...no such ground glass frame modification is needed - but in choosing this route it would be recommended that you install a plain protective glass over the back of the fresnel.
Prior to my modifying my 5x7 back to accommodate the Maxwell setup (fresnel plus gg), I tried using the fresnel mounted behind the ground glass, but found that focussing/viewing was slightly better/easier with the fresnel mounted in front of the ground glass - so I went ahead and made the modification, and since then have been extremely satisfied with this setup.
Keep in mind that Bill Maxwell can supply such fresnel/gg kits in a number of brightnesses and focal lengths, to give the user the best setup for a users needs. For my 5x7, for example, I've chosen a 120mm fl in combo with a medium-fine grind ground glass - and find it amazing with my 90 and 305mm lenses, and simply mind blowing with my 120 and 210mm lenses.
Finding the "best" balance in a ground glass/fresnel system...one that presents a good degree of brightness, evenness, and ability to resolve fine details, when "improving" any of these aspects can result in diminishing the others, is a bit of an art - and requires an understanding of what we LF folks truly need beyond the merely theoretical. Bill Maxwell knows the theory, but he also "gets it," and for this I am very grateful. Furthermore, he is without peer in his skill in creating a fresnel field with extremely fine and precise cuts, so that in practice, the circular pattern that these cuts present are hardly noticeable, whereas with other similar screens from other manufacturers, these circles can be very distracting.
Personally, I place no less value on a good focussing screen setup than I do on a camera or lens, and do what I can to budget accordingly.
The screens that Canham uses are also the all in one fresnel/screen combo. Very nice, quite bright.
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