What makes a good lens?

Michael Rogers

Michael Rogers

What do you look for in a lens?


I guess I've always been curious... how do you know if a lens is good or not? What are the deciding factors for quality when you choose a lens?


I just got an HDSLR after being skeptical of the craze... now I need to learn what needs to accompany it.

Answers?
 
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rayw: there's nothing stopping you from doing this, but you won't be able to get a focused image. You might get some visually interesting shots, but it won't look like anything - try looking directly through an unattached SLR lens, because that's the kind of image you're going to get. 35mm adapters work by focusing the image from a lens on to a ground glass screen, and then recording that image with a camera. It's not a question of "will it be okay quality" but that it's optically and physically impossible.
 
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Chilipie -
FUBAR focus.
I was afraid of that.
I was kinda hoping the focus could be manually adjusted to eventually make something usable, but I totally understand the mechanics/physics of the 50mm lens (or any other) being designed to place a focused image X millimeters behind, hopefully onto film or CMOS chip.
I guess putting it onto the exterior lens of the camcorder isn't going to cut it.
Rats.

You've tried this yourself or have seen someone else give this or something like it a chance?
 
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Michael Rogers said:
Is M42 the most common mount for vintage lenses?
Click to expand...

It's one of them......but its the most easy to adapt because its a screw mount. It does depend on your camera. so if you have a nikon make sure you get a nikon adaptor for a m42 screw mount lens. but there are other vintage mounts that vary so pay attention to what you are buying; Also never get an adaptor that has glass/plastic in it! you dont want an extra piece of glass or plastic between the camera and the lens.

and i just scored another vintage lens, a HELIOS-44-M M42 F= 2/58
so now i have 2 primes that cost me $55 including shipping
and a HANIMAR 135mm F/3.5 LENS $30 with shipping.. i didnt pay attention to what i was buying and got screwed....it will still work but its poorly made and the app is broken fixed.....
 
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I understand there are two different screw thread pitches.
The m42 is the 1mm while the rest are 0.75mm.

Yes/No?


http://photonotes.org/cgi-bin/photo-entry.pl?id=Threadpitch
"Screwmount lenses also have a thread pitch. For example, T-mount lenses are sometimes described as M42 x 0.75, meaning they had a metric diameter of 42mm with a thread pitch of 0.75mm. T-mount lenses are not compatible with M42/Pentax screwmount system, which had a metric diameter of 42mm with a 1mm thread pitch."

Okay, so it's the T-mount lenses that are 1mm.
M42/Pentax are 0.75mm.

Cool.


Seems T-mounts are not too common.
http://www.google.com/search?tbm=is...7995l12l12l0l1l1l0l235l1960l0.10.1l11l0&uss=1
 
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Generally when we say M42 we mean (at least I do) the Pentax M42 mount.

The biggie to avoid (unless you have a GH2 where I think they work) is the Canon FD lenses. They require the aforementioned optical adapter.
 
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