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Old July 1st, 2005, 01:28 PM   #1
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Any help identifying these lenses?

Here are some images of lenses that I have lying around, I need a little help in Identifying them in my search for a condenser -

http://dvstuff.250free.com

Any thoughts?
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Old July 1st, 2005, 03:14 PM   #2
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Leo, the second one is definitely a condenser (from a slide projector?)
The first one could probably be very useful too, perhaps a combination of those two with the GG sandwiched between them.

You need Aaron Shaw for this though...Aaron?
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Old July 1st, 2005, 03:35 PM   #3
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I can't remember where I got it, but it is thick - too thick in fact (you seem to have thin condensers). I think it was from one of those small polaroid slide viewers.
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Old July 1st, 2005, 06:06 PM   #4
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Eek :)

Mandy, can you describe each face of the optics? It's hard to tell what exactly you have from the images. This is what I *think* I see (you will have to verify this):

1) Concave-Convex (curved outward on one side and inward on the other)
2) Plano-Convex lens (curved on one side flat on the other)

The term condenser is a broad term applied to a term applied to lenses or mirrors designed to collect, control, and/or concentrate radiation in an illumination system. Technically, it isn't a lens type in and of itself. Both of the above could be used to condense light (assuming I guessed their types correctly). Which one you use would depend on the system you are designing and the specific condensing properties you desired.
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Old July 1st, 2005, 06:26 PM   #5
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Just had a thought. Maybe it would be useful if I wrote up a short intro to optics? I think it might help people out when deciding what parts they need.
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Old July 1st, 2005, 07:09 PM   #6
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I woke him up allright...
Some words on optics would be great, because most people, including me, are talking half-sense/half-nonsense when it comes to optics.
I was thinking about the same thing about condensers, but it was just based on nothing but some experience by taking apart some lenses and leaning which ones could be used for condensers. What I did with my wax adapter was to put two thin 'condensers' to collect the whole image (like old cameras where you look on top of a lens) and then put a bright GG between to get the DOF.

Last edited by Oscar Spierenburg; July 1st, 2005 at 08:04 PM.
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Old July 1st, 2005, 09:21 PM   #7
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I think it would be a great idea Aaron!

I have put some 4 new images up using the first condenser (or what I think is a condenser) and nothing else in front of the camera) at about 6:30pm. Is it me, or does it still look a little soft? I think my focal length is off, but it might be just the condenser between the GG and the SLR lens that is making it not true. Any thought appreciated.

http://dvstuff.250free.com
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Old July 2nd, 2005, 06:35 AM   #8
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The images are much brighter than before. Some close-up shots seem to be in focus.
For people who have trouble focusing right, I fine tune the camcorder on the GG with everything hooked up to a big monitor or TV screen and focus on Ron Dexter's focus pattern. You can download the PDF on this page:
http://www.rondexter.com/professiona...us_pattern.htm
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Old July 2nd, 2005, 11:48 AM   #9
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How do you set the exact distance at a close focal range though? I have tried this way in the past and found it too difficult. I like the idea of infinity because there is no measuring involved.
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Old July 2nd, 2005, 05:56 PM   #10
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Well, I purchased a new lens today in the charity shop (I have been lucky lately). It is a Konika Hexanon 57mm 1:1.4 fast lens. Nice big front end and nice size back lens. I am moving from the Canon 1.8 to this one and I think it might have a condenser built in!

http://cgi.ebay.ca/ws/eBayISAPI.dll?...527506896&rd=1

I don't know much about Konika, but I know that Nikon, Pentax are the top quality lenses, but you don;t see many of them in the charity shops!

Also on a side note, I am getting tired of going into Henry's (Canada's big Camera place) and the people there having less of a clue then me (and I am pretty dense when it comes to optics - see any of my posts!). I asked about Focusing Screens today and the guy had no idea what they were, but gave me the ubiquitous answer - 'I am sure we can order them!'. Last time I asked about Fresnels, same answer, blank look.
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Old July 2nd, 2005, 07:37 PM   #11
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So it's the same everywhere, their is no expertise anymore.
Konika/Minolta is a pretty good brand, I shot all my wax tests with practically the same lens. Very fast and very nice DOF distortion.
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Old July 2nd, 2005, 08:18 PM   #12
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Thanks for the info, it is cool that we are on the same page, that way I can compare my tests to some of your stuff to see how I am doing!
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Old July 3rd, 2005, 05:30 AM   #13
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And you have probably the same focal distance, so I'll do some tests in the coming days to measure the exact distance from the lens to the GG.
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Old July 6th, 2005, 09:37 AM   #14
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Leo, the distance from the back of the lens (without the bayonet) to the GG is 46 mm for the Minolta 58mm.
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