Cheap fast wide angle- Computar 12.5mm f/1.3 C-Mount (example pics)

It looks like you got a no-name 25mm on EBay? I've not heard great things about those.

The Pentax/Cosmicar 25mm f/1.4 is very good, I think better than my Computar wide. In another thread here a poster actually tested his Pentax 25mm against his Panasonic 20mm, and found the Pentax sharper in the middle. The focus ring on both of my lenses is on the outside, guess I got lucky there.

I only just started shooting with mine, but here is an example with pretty good sharpness, no sharpening has been applied in post yet. Hopefully the expanded view will give you a good look-





No cropping either, so you can see how this lens vignettes. I think the most impressive detail in the shot is not actually the hamster, but the skin texture on my daughter's hand (again, relative to the price we're paying for a really fast M 4/3 prime lens.)

It sells new for $100, but you can find used ones on EBay for less. My older version Cosmicar 25mm was only $20 since the outer ring was dinged.

madmaxmedia said:

It looks like you got a no-name 25mm on EBay? I've not heard great things about those.

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It's not too bad. Focusing is a little bit tricky and it's too close to the very good 20mm f1.7 to be a real winner. I'll be playing a little bit more with it to see whether I'm going to use it more often.

The noname 35mm is a really good one though.

madmaxmedia said:

The Pentax/Cosmicar 25mm f/1.4 is very good, I think better than my Computar wide. In another thread here a poster actually tested his Pentax 25mm against his Panasonic 20mm, and found the Pentax sharper in the middle. The focus ring on both of my lenses is on the outside, guess I got lucky there.

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Indeed, on my Pentax 12mm it's on the inside.

madmaxmedia said:

I only just started shooting with mine, but here is an example with pretty good sharpness, no sharpening has been applied in post yet. Hopefully the expanded view will give you a good look-

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Very nice indeed.

madmaxmedia said:

It sells new for $100, but you can find used ones on EBay for less. My older version Cosmicar 25mm was only $20 since the outer ring was dinged.

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I'm watching ebay.com quite closely. Problem is that most US sellers won't ship to Europe or are asking for absurd P&P. The HongKong/China dudes do not seem to offer that much brand ware.

In Europe the ebays do not usually have brand lenses either and if they do, they're asking for like twice the retail $ price in Euro (!). The Pentax is a spare part for an industrial project I did a while ago, it was a somewhat cheap add-on to an expensive GigE camera; next time I make sure to order some more. :-D Other than that those lenses are only available in security shops and alike and they sure know how to make a quick buck around here...

I really have to do some more shooting, so I can post some example images with a different subject than my son. :-D

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Servus, Daniel

Gato Amarillo said:

Very nice photography. Obviously you're really making this lens work for you.

Gato

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http://www.flickr.com/photos/30657645@N03/

Here are three full OOC shots of an artificial scene for comparison:

In the order: Noname 35mm, Noname 25mm, Pentax 12mm. All wide open and focused on the bezel of the frontmost glass, I have stopped down versions too. I think the 35mm is OOF though. :/













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Servus, Daniel

The bokeh effects on the car in the background (on the left) in the first shot are perfect triangles, which is really odd. I seems as if the diaphragm has only three blades and it was stopped down to f4 or 5.6 in that shot. Is that possible? (Does the diaphragm have only three blades?)

(But otherwise, yes, very nice! I'm looking for a fast MF 12mm, so this might be the ticket for me!)

e
d

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Do the Computar 12.5/1.3 needed to be machine? If so, how? Feel free to redirect me to other site/post if it was answered already. Thanks.

It can be 'machined' by hand. ;-)

But yes, you do have to modify it. You can use a file and do it yourself with some time but not too much difficulty.

Scroll down this page, I posted a pic of my lens-

e-p1 DOT net/lenses/how-to-tell-if-it's-the-1'-version-of-a-computar-12-5mm/msg31675/#msg31675

madmaxmedia said:

It can be 'machined' by hand. ;-)

But yes, you do have to modify it. You can use a file and do it yourself with some time but not too much difficulty.

Scroll down this page, I posted a pic of my lens-

e-p1 DOT net/lenses/how-to-tell-if-it's-the-1'-version-of-a-computar-12-5mm/msg31675/#msg31675

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Thanks. I better stay away from c mount then...

madmaxmedia said:

It can be 'machined' by hand. ;-)

But yes, you do have to modify it. You can use a file and do it yourself with some time but not too much difficulty.

Scroll down this page, I posted a pic of my lens-

e-p1 DOT net/lenses/how-to-tell-if-it's-the-1'-version-of-a-computar-12-5mm/msg31675/#msg31675

Click to expand...

Hi. I finally buy some C mount lens:
Computar 25mm f1.4
Cosmicar 16mm f1.6
Fujinon 35mm f1.7

Could you give me some advice to use these lenses? Some kind of modification is needed, right? Is it similar to your guide before? By the way, I can't enter the site you shared before.

LOL, did you buy them as a lot on EBay? I was watching that auction! ;-) (but didn't bid)

Send me an email, and I can try to help. I haven't used those lenses before, so not sure if you will need to modify them.

Do you have a c-mount to M/43 adapter yet?

madmaxmedia said:

LOL, did you buy them as a lot on EBay? I was watching that auction! ;-) (but didn't bid)

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Exactly. Why don't you buy it then? It is not a good deal?

madmaxmedia said:

Send me an email, and I can try to help. I haven't used those lenses before, so not sure if you will need to modify them.

Do you have a c-mount to M/43 adapter yet?

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Not yet. I am not sure which adapter I should buy. Do you have any idea?

Hi kolen,

It looked like a good deal, but I didn't need more lenses right now.

Hopefully the minor marks described by the seller are just that- minor. I was watching the auction and then later removed it from My EBay (to not tempt myself), so I don't know what they ended up selling at.

Adapters sold by Hawks Factory on EBay are said to be well made and designed, as they are more tolerant for fit. So that's the kind I bought, although you can find cheaper adapters as well. Check EBay item 320646037403. 330528026598 is a much cheaper one, and may work just as well.

My guess is that at least 1 of your new lenses will probably fit without modification, and at least 1 will require modification. Just hopefully not all 3!

Steve