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02-20-2020, 12:28 PM   #1
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M42 Enlarger Lens adaptaer help?

Hello, nice to greet you all

Recently acquired an enlarger m42 lens on ebay for $ 1. This type of lens has no focusing mechanism so an adapter is required.

Checking on ebay and amazon I see different focal lengths of the adapters which generates a doubt to buy the right one.

The enlarger that I acquired is a: AMAR PZO Red P f4.5 / 105mm M42 (attached image) looks like a normal m42 lens, have 10 blades, but dont have the focus ring.

In amazon I found the following adapters m42 to m42 ranging from 12mm to 90mm. (attached image)

My question is if I buy for example the adapter 35-90mm will I transform the enlarger that is originally a 105mm fixed to a zoom lens? And if I buy the 15-26mm I transform it into a wide lens?

Or regardless of the adapter will I always have 105mm? How does this work for this type of lens?

I can't find a specific adapter for 105mm.

I appreciate the help you can give me.

Have a nice day

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02-20-2020, 12:53 PM   #2
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M42 is unusual for an enlarging lens. I suspect the most common is Leica 39mm. Are you going to use this on an enlarger? On an enlarger the focusing system is part the enlarger. If you are wanting to use the lens for taking pictures you will need to have a focusing bellows of the type commonly used for close focusing. No adapter changes the focal length of the lens. I have used a 100mm enlarging lens for close-up pictures with my Pentax bellows II unit.
02-20-2020, 01:12 PM   #3
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QuoteOriginally posted by pentaxus Quote
M42 is unusual for an enlarging lens. I suspect the most common is Leica 39mm. Are you going to use this on an enlarger? On an enlarger the focusing system is part the enlarger. If you are wanting to use the lens for taking pictures you will need to have a focusing bellows of the type commonly used for close focusing. No adapter changes the focal length of the lens. I have used a 100mm enlarging lens for close-up pictures with my Pentax bellows II unit.
That is what I do not know, in the description of the article on ebay it says that it is an enlarger but I am very new in that, I want it to take photos so I want to be guided to know what I should buy or do so that I can focus?
02-20-2020, 02:29 PM   #4
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There are quite a few posters on mflenses.com who use enlarger lenses.

02-20-2020, 02:39 PM - 1 Like   #5
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You will need a bellows to focus since the lens has no provision for that. The bellows goes between the lens and your camera (adapters probably needed at each end) and allows the distance from your lens to focal plane to be varied.

AN enlarger lens can be used quite well for macro photography (photography of close small objects), but probably isn't optimum for distant objects since the optical formula of an enlarger lens usually isn't designed for that use.
02-20-2020, 02:43 PM   #6
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Doing some preliminary searches. The lens appears to be indeed M42 mount, unusual for an enlarger but not improbably since enlarger lenses are typically mounted on a removable plate with a retaining ring. So long as a plate and ring are available you can mount different diameter mounts on the enlarger.

Here's a blog entry. The blogger mounted it on a Pentax M42 bellows.

PZO Amar 10.5cm (105mm) F/4.5 Enlarger Lens – Test | JVG's Photo Blog
02-20-2020, 04:25 PM - 1 Like   #7
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Greetings, enlarger lenses can be great fun.
If you do have a native M42 mount instead of a t mount your adaption will be much easier.
Depending on what you're trying to photograph you can use a bellows, helicoid (the items you mentioned in your post) or mount straight to camera for macro.
The issue you will face is the focusing distance, the 105 will stay a 105, but how close or how far you will achieve focus will be your limits.
Just tested my Omicron 80 (I use for UV photography) and Rodenstock 105 with a 25-55mm helicoid.
My enlarger lenses are all L39, so I use an adapter from L39 to M42 which adds an additional 4.5mm or so, so roughly a 30-60 helicoid.
The 105 can focus from infinity (part way out the helicoid) to about 36 inches close focus distance, the 80 will focus from about 25 feet to around 18 inches close focus.
I just know the distance my lenses will focus with the setup I use and then choose which lens for the subject I'm shooting.
Hope this helps and have fun.

---------- Post added 02-20-20 at 03:55 PM ----------

Just wanted to add into what @Bob 256 mentions.
With the 105, I was able to hit focus peaking in LV on some rock outcrops about 5 miles away but I wouldn't say it would be a good quality image due to the lens optic limitations.
At 36 inches it is tack sharp.
Most enlarger lenses are made for a close focusing distance, learn the strengths and weakness of the lens and then go from there.
02-20-2020, 05:19 PM   #8
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QuoteOriginally posted by pcrichmond Quote
Greetings, enlarger lenses can be great fun.
If you do have a native M42 mount instead of a t mount your adaption will be much easier.
Depending on what you're trying to photograph you can use a bellows, helicoid (the items you mentioned in your post) or mount straight to camera for macro.
The issue you will face is the focusing distance, the 105 will stay a 105, but how close or how far you will achieve focus will be your limits.
Just tested my Omicron 80 (I use for UV photography) and Rodenstock 105 with a 25-55mm helicoid.
My enlarger lenses are all L39, so I use an adapter from L39 to M42 which adds an additional 4.5mm or so, so roughly a 30-60 helicoid.
The 105 can focus from infinity (part way out the helicoid) to about 36 inches close focus distance, the 80 will focus from about 25 feet to around 18 inches close focus.
I just know the distance my lenses will focus with the setup I use and then choose which lens for the subject I'm shooting.
Hope this helps and have fun.

---------- Post added 02-20-20 at 03:55 PM ----------

Just wanted to add into what @Bob 256 mentions.
With the 105, I was able to hit focus peaking in LV on some rock outcrops about 5 miles away but I wouldn't say it would be a good quality image due to the lens optic limitations.
At 36 inches it is tack sharp.
Most enlarger lenses are made for a close focusing distance, learn the strengths and weakness of the lens and then go from there.
I think I already understood, if I buy a 25-59 mm helicoid I will be able to focus at about 36 inches (90 centimeters) or so but I need to consider the original focal length of 105mm, is that correct? Taking this into account, should I buy a 35-90mm helicoid to have a greater margin of possible focus? or does it not necessarily happen that way?

02-21-2020, 12:47 AM - 2 Likes   #9
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The calculations involved in determining extension and magnification are not very difficult to make. Focal length of a lens can be defined as the distance from lens optical center to the plane of first sharp focus (Infinity). Also focal length is 1/2 the distance from optical center to the plane of an image measuring the same size as subject (lifesize). The flange distance to focal plane for Pentax K and M42 is fixed at 45.46 mm. The necessary distance for any focal length lens to focus at infinity is that focal length as measured from the optical center to focal plane. Enlarging lenses normally have a predictable symmetrical design so the optical center would predictably be at or near the physical center of the lens. Simply, to focus at infinity, your lens with no helicoid will require 105 - 45.46 = 59.54 mm of extension. So at lifesize macro (1:1 magnification) your will need 105mm more (164.54) to total 210mm at which the subject to lens center distance will also be 210mm.
02-21-2020, 09:54 AM   #10
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Looking at the price of the helcoid adapters (Fotodiox) you could buy a nice 105mm MF prime instead.
02-21-2020, 10:39 AM - 1 Like   #11
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Thanks @From1980. Nice simple explanation of extension to FFD calculation. I'll keep this written down for a couple Cooke triplets I'm adapting now for close focus UV photography.
@ric_cr, the 35-90 should give you an inexpensive starting point to see how the lens performs.
See where the focus limits are when you have it set up and adjust your shooting style from there. You can always add shorter extension tubes for close focus / macro work.
02-24-2020, 10:34 AM   #12
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QuoteOriginally posted by Bob 256 Quote
You will need a bellows to focus since the lens has no provision for that. The bellows goes between the lens and your camera (adapters probably needed at each end) and allows the distance from your lens to focal plane to be varied.

AN enlarger lens can be used quite well for macro photography (photography of close small objects), but probably isn't optimum for distant objects since the optical formula of an enlarger lens usually isn't designed for that use.
There is an m42 focusing helix that Pentax made, if you have the right length extension tube plus focusing helix, you would be all set.
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