Using old lenses - Feature Requests - CHDK Forum
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Using old lenses

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gergilar

Using old lenses
« on: 27 / December / 2007, 08:45:41 »
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Hi people.
Chdk is a GREAT JOB!.
I made an adaptor to use my old yashica reflex lenses (zoom, macro) in my 570is and it's working quite fine, but i have solved the flipping invertion of the image using pentaprisma's (first instance) and then using lenses (39 cm aluminum tube cannon to get the standing image).
I think that could be a great feature in chdk to make this flipping invertion on the fly by software and seen flipped image on lcd. With this issue solved by chdk i can remove arround 30 cm of tube and lots of lenses.
Is this possible? ;)
Sorry, my english is poor.

Re: Using old lenses
« Reply #1 on: 27 / December / 2007, 12:33:52 »
Deleted
« Last Edit: 22 / April / 2008, 09:09:14 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye

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gergilar

Re: Using old lenses
« Reply #2 on: 27 / December / 2007, 15:04:32 »
Hi Barney Fife.
Yes, I agree with you about this fun experiment with stacking glass  :-[, but i'm taking nice pictures using this lenses.
I'm not a professional, just love photography and prefer to give new use to this old abandoned stuff.
The target of my proyect is to try to use that great old SLR lenses.
I'll hate to drop them in garbage or use them as a perfect place for fungi  :xmas.

Re: Using old lenses
« Reply #3 on: 27 / December / 2007, 15:21:17 »
While I understand why you'd want to see if using those lenses would work, you do realize that using simple wide-angle and tele-converter adapters would be your better bet, don't you?

Stacking that much glass in front of an already existing camera lens will degrade the image greatly. Every glass-to-air surface robs an image by as much as 5% contrast and light levels.

It's a novel idea, to use old SLR lenses for this, but really .... :D ... you need to be using simpler lenses in front of your camera's lens. I have an old 55mm that I use with a reverse coupler for extreme macro-photography, but I wouldn't even think of mounting any of my old zoom and other macro lenses out in front of my normal Powershot lens.

Do a test of TRUE resolution comparing the images that you can get with tele-extenders and normal single-element or single-element achromat close-up lenses, compared to the way you are doing it now. I bet you are getting at least 1/2 the resolution that you can get by using simpler methods with less glass.

That's a fun experiment with stacking glass, but I don't think you thought this through completely. :)


You do realize you will never get the beautiful DOF as with old SLR lenses, right? :)
I'm making the same contraption, and this would be nice if it could be done with CHDK.
However, Gergilar, I do think it is a lot better to already cut down on the glass, and just hold the camera upside down. It would increase the quality greatly. ^ ^ (What are you using as ground glass?)


Re: Using old lenses
« Reply #4 on: 27 / December / 2007, 16:05:16 »
Deleted
« Last Edit: 22 / April / 2008, 09:09:35 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye

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gergilar

Re: Using old lenses
« Reply #5 on: 28 / December / 2007, 08:10:15 »
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Ground glass? What are you doing? Trying to focus on the image from the SLR lens that's focused on ground glass?
Agree with Barney Fife, what to use ground-glass for?, just use the image obtained behind the lens.

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just hold the camera upside down
??, the image is flipped! i need to be myself upside down  ;)...

I'm wondering if this new feature of CHDK is simple and possible or not?.

 

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