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Some questions about the projector lenses?
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PostPosted: Wed Feb 25, 2015 8:04 am    Post subject: Some questions about the projector lenses? Reply with quote
How is the distance D between the sensor and the lens needed to focus between infinity and 1: 1 with a projection lens?
It is valid the rule D = FL (focal length of the lens) for focus to infinity and D = 2xFL for 1:1 focus?
Unlike an enlarging lens that resembles a pancake lens, the projector lenses are long cylinders. Where is the optical center? It's ok if it is considered in the mid of the cylinder projection lens? These lenses performs well for 30-50-100m focus distance? Are they ok for close-up photography, too?


PostPosted: Wed Feb 25, 2015 11:11 am    Post subject: Reply with quote
This is probably the most popular projector lens at the moment.
http://forum.mflenses.com/viewtopic.php?t=55218
Never tried it for macro.


PostPosted: Wed Feb 25, 2015 5:27 pm    Post subject: Reply with quote
Really interesting lens ... but kinda expensive for someone who still does not know how to mount the projection lenses on a DSLR Smile


PostPosted: Wed Feb 25, 2015 10:22 pm    Post subject: Re: Some questions about the projector lenses? Reply with quote
edri wrote:
How is the distance D between the sensor and the lens needed to focus between infinity and 1: 1 with a projection lens?
It is valid the rule D = FL (focal length of the lens) for focus to infinity and D = 2xFL for 1:1 focus?
Unlike an enlarging lens that resembles a pancake lens, the projector lenses are long cylinders. Where is the optical center? It's ok if it is considered in the mid of the cylinder projection lens? These lenses performs well for 30-50-100m focus distance? Are they ok for close-up photography, too?


I do a lot of macro with these, my thing it is. I have adapted them from infinity to very close up.
Here are results if you'd like to browse through: https://www.flickr.com/photos/kds315/sets/

Here that mentioned MEOPTA 1.4/70mm
Infinity:


Close-up:



and here a Dutch Delfinor 75mm at closeup:


PostPosted: Wed Feb 25, 2015 10:44 pm    Post subject: Reply with quote
edri wrote:
Really interesting lens ... but kinda expensive for someone who still does not know how to mount the projection lenses on a DSLR Smile

hinnerker sells them ready to mount with the DSLR mount of your choice. PM him here: http://forum.mflenses.com/privmsg,mode,post,u,1806.html
http://forum.mflenses.com/meopta-meostigmat-1-4-70-on-ff-and-nex-via-vnex-t55218,start,90.html#1409293


PostPosted: Thu Feb 26, 2015 7:46 am    Post subject: Reply with quote
edri wrote:
Really interesting lens ... but kinda expensive for someone who still does not know how to mount the projection lenses on a DSLR Smile


All you need is a focusing helicoid, a camera adapter and a lens adapter. And such a lens of course. If you like to use it on a DSLR (with mirror), you'll need a rather long focal length to make it fit, usually from about 100mm focal length onwards. I woudl try a russian lens, as they can be had for little, like the Lomo 35КП f1.8 100мм https://www.flickr.com/photos/kds315/sets/72157644011296955/. Those have 62.5mm diameter.

Rafcamera.com sells those adapters on ebay or on their site.


PostPosted: Thu Feb 26, 2015 8:25 pm    Post subject: colorplan Reply with quote
And if you wish to use a first class leica lens, Hinnerkers adapters will let you use the Colorplan, which judged from the lens diagram, is like the 90mm Elmarit. OF course, the radii and the glass and consequently internal distances might be subtly different, but as it performs well converting a 35mm Kodachome slide to a 200cm high luminous picture, I assume that it will perform equally well in converting a larger subject down to 24x35mm. I have not used his projection lens adapter, but am very pleased, both with his Vnex device and his follow up.

p


PostPosted: Fri Feb 27, 2015 10:59 am    Post subject: Reply with quote
Thanks for information on adaptation the projector lenses.
I prefer the Pentax DSLR because I do not have anything. Smile Until I joined this forum I never realized what great advantages provided mirrorless cameras. Why just over 100mm lenses? I was thinking to try Pentacon 80/2.8 and Leitz 90/2.5. After responses on this topic it is interesting Meopta 70/1.4 as well. But they are not a bargain. That means giving up the idea of lenses that I thought, because is it possible to can not adjust correctly?
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