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07-16-2009, 04:19 AM   #1
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DSLR-SLR lens misery

Hi everyone! I have a Pentax K-m with 18-55 lens, and I'm thinking about getting a teleobjective. I found a pack wich contains a
Pentax MZ 50 + a Cosina 100-300 lens. I'm wondering if i could use my lens with both bodies vica-versa with or without AF. They have the same type of hotshoe for flash, i guess, but i'm not sure about it. So anyone can help, please answer! Thanks!

07-16-2009, 04:30 AM   #2
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Welcome to the forum.
Firstly, you have a very capable camera in the K-m.

Pentax prides itself with having the backward compatibility with any lens that will mount to the camera - which is true, any lens that fits will work, and the SR mechanism will still be available. So although your 18-55 kit lens is not supposed to work on the MZ-50, any lens you put on your K-m will definitely work, as long as you've indicated on the menu option that the camera should accept non-A lenses (for M lenses you want to fit on the K-m).

As for flashes, you'll find that unfortunately the K-m does not have TTL provisions - so a TTL flash that would normally work on the MZ-50 will not behave as a TTL flash on the K-m. Rather, it will work fine as an M flash (manual settings) in M mode on the camera. Though if you're looking for an auto flash for the K-m, best to go with a P-TTL capable flash.

All the best in that.
07-16-2009, 05:21 AM   #3
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Welcome to the forum!

I'm sure you'll have a great time with both your new toys!

Your MZ-50 has the crippled KAF mount - see Bojidar Dimitrov's Pentax K-Mount MZ50 pages (there are heaps of other specs too), so the AF feature and auto aperture work fine.

The DA18-55 that came with your K-M should work with the MZ-50, but its designed for APS-C sensors (smaller than film), so it will probably produce a vignetting effect.

Whereas the Cosina 100-300 should work fine on the KM, and give you a 35mm equivalent of 150-450mm (ie multiply the focal length by 1.5 to find what its 35mm equivalent). Not sure about its AF or other functionality.

WARNING: You may have a problem with older flash units on your K-M - older flash units had high voltages across the contacts that can fry your digital camera electronics.

07-16-2009, 06:35 AM   #4
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to make it clear, i don't have the mz50, i'M just thinking about buying one. My actual regular camera is a zenit TTL with pentacon 4/200 tele, and with helios 2/58 lens. I was planning to buy a converter so that i could use the pentacon lens with my K-m in manual mode, but now i think the best would be if i can sell the zenit stuff, and buy a regular pentax machine with an AF teleobjective wich is compatible with my K-m vica-versa. However I don't know much about this compatible-or-not-compatible stuff, so if you have any ideas pleas post it.

07-16-2009, 08:05 AM   #5
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K-M + cosina 100-300: You didn't tell us whether the lens is an AF lens or not, if it's an AF lens that works with MZ-50's AF, then it should work just fine on the K-M

MZ-50 + DA18-55: Looking at dimitrov's site I'm pretty sure that MZ-50 has an in-body aperture control so the lack of aperture ring on 18-55 shouldn't be an issue. Like said above used above 23mm you shouldn't have an issue, under 23mm you'll have vignetting.

Unless the MZ50 and cosina package is under 60$ and is actually an AF lens, I would just get a DA 50-200 really as it's cheap enough and relatively decent performer.

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