A frosted bulb generates heat. The glass is to absorb heat to prevent the negative from buckling.
I wonder if I can just place a frosted LED bulb of the same dimensions. The bulb thread in Omega is just regular bulb thread correct? Can't check now, as I'm at work.
A frosted bulb generates heat. The glass is to absorb heat to prevent the negative from buckling.
How about this one, 6.5" diameter, should fit into the condenser lens tray. Just not as expensive as other ones.
How about this one, 6.5" diameter, should fit into the condenser lens tray. Just not as expensive as other ones.
What brands do you guys use? Yesterday tried the 80mm Componon on a 4x5, and the illumination appeared even, not sure about the focus. The 75mm 4-element Wollensak started to produce distortion. No I will not use 80mm Componon for 4x5, but just as a demonstration I think because it's a 6 element design, it can do more than 4-element.
By the outside look of the lens, the 6-element lenses all tend to have long bodies (to accommodate the lens stack) and front/rear elements with a very round surface, small radius of curvature. Noticed that all wide angle lenses have this strong curvature, either positive or negative, probably making it more expensive to machine.
I have these two guys in transit:
View attachment 332646 View attachment 332647
and a 4-element
View attachment 332648
Not sure you'll get to use the 190 and 210 without an added 2-3 inches on your cone.
See what I had to do to fit the 150mm, this was a cone for a 105mm...
Not sure you'll get to use the 190 and 210 without an added 2-3 inches on your cone.
Mind sharing the details of the LED bulb make/size?I use a regular-size LED bulb. Nothing gets hot but it does boost contrast. Illumination is even for 4x5.
You may as well try it. Spending $4 on a bulb and seeing for yourself is faster than reading spurious opinions online.
also can you share some details of that focusing know mod? I have to put my face near the easel on the grain finder while holding up my arm if the weirdest manner. It makes for a good stretching exercise but not for fine darkroom work.See what I had to do to fit the 150mm, this was a cone for a 105mm...
Yes, did you manage to keep the lens alignment this way? It's a homebuilt modification, with carbon fiber or what is it? I now have a couple of lens cones, one of them is quite long, so hopefully I won't need this for my 190/210mm.
Mind sharing the details of the LED bulb make/size?
See what I had to do to fit the 150mm, this was a cone for a 105mm...
Well I'm thinking of making 8x10 color contact prints. But also I'm thinking 4x5 negatives enlarged to 8x10 or so may be just as sharp as 8x10 contacts and less expensive, as color 8x10 film is like $30/sheet. A longer focal length lens should be less susceptible to film buckling issues, enlarger misalignment, and be more sharp across the field. The smaller the angle, the easier it is to make a sharp image as I understand. Also dust should be a lesser issue, as dust particles are not being enlarged as much.I don't know, but by the time you get a 210 lens on the enlarger and focus the 4x5 negative with the enlarger head at the top of the mast, I think your projection will be something less than 8x10 inches.
A contact print will always be sharper than an enlarged one, given the same film and processing. The advantage of a longer focal lens is you will only be using the sweet spot and not the edges, so the enlarged image should be sharper and more even edge to edge. The downside is you won't be able to enlarge it as much. The lens has absolutely nothing to do with film buckling, that is due to the flatness of the negative. A cold light source such as an LED that emits the proper spectrum (not a cold light head that needs diffusion and will not produce as sharp an image) or better yet, a glass negative carrier should deal with that. Dust is dust and if I understand you are comparing an 8x10 negative contact print to an 8x10 enlargement from 4x5 film, the lens once again has nothing to do with it, the 4x5 dust will be larger, but there is more chance the 8x10 will have the possibility of more dust, just because of the relative surface area. Try to work in a dust-free environment and clean your film carefully and well, and dust will be less of an issue.Well I'm thinking of making 8x10 color contact prints. But also I'm thinking 4x5 negatives enlarged to 8x10 or so may be just as sharp as 8x10 contacts and less expensive, as color 8x10 film is like $30/sheet. A longer focal length lens should be less susceptible to film buckling issues, enlarger misalignment, and be more sharp across the field. The smaller the angle, the easier it is to make a sharp image as I understand. Also dust should be a lesser issue, as dust particles are not being enlarged as much.
What brands do you guys use? Yesterday tried the 80mm Componon on a 4x5, and the illumination appeared even, not sure about the focus. The 75mm 4-element Wollensak started to produce distortion. No I will not use 80mm Componon for 4x5, but just as a demonstration I think because it's a 6 element design, it can do more than 4-element.
By the outside look of the lens, the 6-element lenses all tend to have long bodies (to accommodate the lens stack) and front/rear elements with a very round surface, small radius of curvature. Noticed that all wide angle lenses have this strong curvature, either positive or negative, probably making it more expensive to machine.
I have these two guys in transit:
View attachment 332646 View attachment 332647
and a 4-element
View attachment 332648
Contact print may be sharper, but the idea is that 4x5 to 8x10 enlargement with a very good setup is the closest to a true 8x10 contact print. Enlargement from 4x5 to 8x10 paper should make the dust less prominent than from 35mm to 8x10. On 35mm it's a problem because a small speck that you didn't catch will be enlarged by a lot. There's not much enlargement from 4x5 to 8x10, and even if there's more area to gather dust, it will not be magnified as much. I think micro dust specks are not really an issue, kind of like on contact prints from a dusty negative, since there's no magnification and you have to peer really hard to see the dust specks. Regarding the film buckling; enlarging from 4x5 to 8x10 using lets say 135mm lens should be a bit more sensitive to film buckling than enlarging with 210mm lens to 8x10. The shorter the focal length the more impact of the uneven negative.Dust is dust and if I understand you are comparing an 8x10 negative contact print to an 8x10 enlargement from 4x5 film, the lens once again has nothing to do with it, the 4x5 dust will be larger, but there is more chance the 8x10 will have the possibility of more dust, just because of the relative surface area. Try to work in a dust-free environment and clean your film carefully and well, and dust will be less of an issue
35mm was never mentioned, this seems to have become just a theoretical discussion for the sake of it. And please explain why a 135mm lens would be more sensitive to the effects of film buckling than a much longer 210mm? Are you sure you will be able to make an 8x10 enlargement using a 210mm lens that the enlarger was never designed to be equipped with?Contact print may be sharper, but the idea is that 4x5 to 8x10 enlargement with a very good setup is the closest to a true 8x10 contact print. Enlargement from 4x5 to 8x10 paper should make the dust less prominent than from 35mm to 8x10. On 35mm it's a problem because a small speck that you didn't catch will be enlarged by a lot. There's not much enlargement from 4x5 to 8x10, and even if there's more area to gather dust, it will not be magnified as much. I think micro dust specks are not really an issue, kind of like on contact prints from a dusty negative, since there's no magnification and you have to peer really hard to see the dust specks. Regarding the film buckling; enlarging from 4x5 to 8x10 using lets say 135mm lens should be a bit more sensitive to film buckling than enlarging with 210mm lens to 8x10. The shorter the focal length the more impact of the uneven negative.
I used the 35mm lens as an exaggerated example. Saying that enlarging from 35mm to 8x10 may be less problematic in terms of dust and film bucking than from 4x5 to 8x10. The best 8x10 print is a contact print no doubt.35mm was never mentioned, this seems to have become just a theoretical discussion for the sake of it.
I used the 35mm lens as an exaggerated example. Saying that enlarging from 35mm to 8x10 may be less problematic in terms of dust and film bucking than from 4x5 to 8x10. The best 8x10 print is a contact print no doubt.
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