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07-02-2011, 09:24 AM   #1
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645 lenses on DSLRs - are they as good or better than their 35mm equivalents?

I am considering the 645 A*300/4 (which I really shouldn't because I want AF for birds).

What is it like compared to the 35mm A* or FA* lenses? Of course it's bigger and heavier but what about the quality?

07-02-2011, 01:00 PM   #2
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Likely to be better I'd have thought. Because you're using the very centre of the lens, so less distortion.
07-02-2011, 06:46 PM   #3
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AF for birds eek. MF is the way to go, more control especially when the little sods are playing hidies amongst twigs and branches.
Can't help with your query about long Medium Format lenses though. I'm also being similarly tempted by a 6x7 lens and equally curious about experiences.
07-02-2011, 10:10 PM   #4
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QuoteOriginally posted by xjjohnno Quote
AF for birds eek. MF is the way to go, more control especially when the little sods are playing hidies amongst twigs and branches.
Can't help with your query about long Medium Format lenses though. I'm also being similarly tempted by a 6x7 lens and equally curious about experiences.
I have an SMC Takumar 300/4.0 P67 lens that I bought because I got curious like yourself, and since I already had the P67->P645, and P645->PK adapters that I could use to mount the lens to my K20D, it seemed like a good idea.

This lens on my K20D is sharp wide open but is very heavy. This lens also has an MFD of 5m - not much good for close-up. It has no tripod collar on the lens and I wasn't about to mount the tripod to the body with almost 2Kg in front of it. Subsequently, I bought an aftermarket P67->PK adapter with a tripod mount (non-rotating, unfortunately) that let me safely mount it to a tripod or attach a home made palm support for the lens, enabling me to hand hold the lens for an extended period of time.

I haven't shot as much as I would have liked to with this lens, perhaps I will try to make a conscious effort to do so soon, but sooner or later I will have start trimming my lens collection if I hope to acquire the K-5 before the next model ships.

Thanks,

07-03-2011, 02:22 AM   #5
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Well I had one on my K-5 just rescently:






It was 645 FA 300mm/f4 and that is a big lens. It is not working very plesantly since you are short one hand to work nicely, but the image quality when you hit something is very good!

Last edited by RonHendriks1966; 07-03-2011 at 11:23 AM.
07-03-2011, 10:04 AM   #6
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On the 645s and the 6x7 lenses on a FF35 or DSLR:

I wouldn't buy those lenses and adapters just to do it but if you have a larger format system they work fine with the obvious disadvantages of size, manual focus, t pod mount and metering. I came across a free 6x7 Taky 135 macro and aquired the K mount adapter and it has been fun. The old taky is such a nicely built old lens. It does add mass to your camera assy. On the other hand there are some very good reasonably priced oldies out there sitting around. Just my 2 cents.
07-23-2011, 12:05 PM   #7
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QuoteOriginally posted by DanielT74 Quote
I am considering the 645 A*300/4 (which I really shouldn't because I want AF for birds).

What is it like compared to the 35mm A* or FA* lenses? Of course it's bigger and heavier but what about the quality?
Why you would need to get A*300mm in 645 whereas the A*300mmF4 in 35mm format is so tiny and effective?

For fast subject, it excels too

Price wise both should be in the same range. Size and weight wise the 35mm format wins hands down

??? 300mmF4 - Pentax Fans Club

Daniel
07-23-2011, 12:11 PM   #8
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QuoteOriginally posted by RonHendriks1966 Quote
Well I had one on my K-5 just rescently:






It was 645 FA 300mm/f4 and that is a big lens. It is not working very plesantly since you are short one hand to work nicely, but the image quality when you hit something is very good!


I cannot resist the temptation putting it side by side with those from the little brother of 35mm format













Daniel

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