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11-01-2010, 07:08 AM   #1
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K-r with manual lenses, first impressions.

So I picked up my K-r body today and as I'm mainly a manual focus guy I thought I'd share my first impressions with this new body and vintage lenses. My previous body was K200D (for sale in the marketplace btw ) and so far I've found some things have changed and some haven't.

In M-mode green button works pretty much the same as before (once I tweaked the settings of course).:

- When pressing the green button with M or K lens the mirror flips very briefly up when closing the aperture to meter (on K200D it didn't). I've heard it's like this also in K-X.

- With M42 lenses there's no sound, the shutter speed changes but the aperture actuation arm or mirror doesn't move. I don't know if it was like this with K-X but coming from K200D this is nice! I'm so used to the K200D "closing" the aperture even with M42 lenses that first I thought nothing happened when I pressed the button.

- in LV the green button metering flips the mirror down and up again and this takes about 1sec.

Av-mode with M42 lenses seems pretty much the same as in K200D:

- I have to dial ~+2EV to get correct(ish) exposure with M42 glass. But that still leaves me ~+1EV to spare when with K200D +2 was all you had. I did a small test with Helios-44 and with +2EV comp exposure stayed pretty consistant through the aperture range and only shifted towards overexposure at smaller apertures.

Looks like the focusing screen can be changed just as easily as in older bodies. The viewfinder is brighter than in my K200D but this might be also due the splitscreen in my K200D (vs the stock screen in K-r).

I will report back once I've used this cam some more.

11-01-2010, 08:34 AM   #2
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QuoteOriginally posted by ovim Quote
- I have to dial ~+2EV to get correct(ish) exposure with M42 glass. But that still leaves me ~+1EV to spare when with K200D +2 was all you had. I did a small test with Helios-44 and with +2EV comp exposure stayed pretty consistant through the aperture range and only shifted towards overexposure at smaller apertures.
I've heard some people say that the Green button metering is better on K-7, K-x and onward, as compared to earlier Pentax models. That is obviously not what you're finding and not what I've found either. My K100DS, K20D and K-x all meter the same way on my K and KA lenses (i.e. they meter correctly wide open and overexpose when stopped down).
11-01-2010, 08:38 AM   #3
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QuoteOriginally posted by audiobomber Quote
I've heard some people say that the Green button metering is better on K-7, K-x and onward, as compared to earlier Pentax models. That is obviously not what you're finding and not what I've found either. My K100DS, K20D and K-x all meter the same way on my K and KA lenses (i.e. they meter correctly wide open and overexpose when stopped down).
I was talking about Av-mode there...
QuoteOriginally posted by ovim Quote
Av-mode with M42 lenses seems pretty much the same as in K200D:

- I have to dial ~+2EV to get correct(ish) exposure with M42 glass. But that still leaves me ~+1EV to spare when with K200D +2 was all you had. I did a small test with Helios-44 and with +2EV comp exposure stayed pretty consistant through the aperture range and only shifted towards overexposure at smaller apertures.
and didn't test M with green button very extensively yet.
11-01-2010, 08:42 AM   #4
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QuoteOriginally posted by ovim Quote
I was talking about Av-mode there...


and didn't test M with green button very extensively yet.
Sorry, I guess I wasn't paying attention. My lenses meter correctly wide open in Av mode.

11-01-2010, 08:56 AM   #5
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QuoteOriginally posted by ovim Quote
...
- When pressing the green button with M or K lens the mirror flips very briefly up when closing the aperture to meter (on K200D it didn't). I've heard it's like this also in K-X.
...
Congrats on new kit :-) I got a k-x just before the k-r hit the sheves. Looking this in a positive way, this saved me a lot of grief in deciding what to get ;-)

Nitpick: with the k-x the mirror stays put, it is just the aperture being briefly closed that makes the sound. Since there is no sound with M42s, I'd expect this to be the same with the k-r. The green button metering (still) being off, especially with M42 lenses, is mystifying (as to the why?), but having seen it mentioned so often I suppose the issue is real, though.
11-01-2010, 10:30 AM   #6
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QuoteOriginally posted by ovim Quote
Av-mode with M42 lenses seems pretty much the same as in K200D:

- I did a small test with Helios-44 and with +2EV comp exposure stayed pretty consistant through the aperture range and only shifted towards overexposure at smaller apertures.
In Av mode the camera doesn't stop down to meter, because it always takes the photo with the aperture wide open. It doesn't matter what aperture you set on the lens, the photo is taken at the widest aperture.
11-01-2010, 10:39 AM   #7
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QuoteOriginally posted by audiobomber Quote
In Av mode the camera doesn't stop down to meter, because it always takes the photo with the aperture wide open. It doesn't matter what aperture you set on the lens, the photo is taken at the widest aperture.
The k-x stops down the lens for exposure in Av mode too. I'd expect the other models to do this as well. Hence, Av mode is useful for M42 lenses (or for wide open when using a k-mount lens with the aperture level).
11-01-2010, 11:11 AM   #8
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QuoteOriginally posted by jolepp Quote
The k-x stops down the lens for exposure in Av mode too. I'd expect the other models to do this as well. Hence, Av mode is useful for M42 lenses (or for wide open when using a k-mount lens with the aperture level).

So M42 lenses behave differently that K-mount manual lenses?


Last edited by audiobomber; 11-01-2010 at 11:25 AM.
11-01-2010, 11:26 AM   #9
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QuoteOriginally posted by jolepp Quote
Nitpick: with the k-x the mirror stays put, it is just the aperture being briefly closed that makes the sound. Since there is no sound with M42s, I'd expect this to be the same with the k-r. The green button metering (still) being off, especially with M42 lenses, is mystifying (as to the why?), but having seen it mentioned so often I suppose the issue is real, though.
K-X users on this thread seem to disagree with you about the mirror moving when metering with the green button. In my K-r I can also clearly hear/see the mirror flipping, even with a M-lens set to it's largest aperture the viewfinder briefly blacks out completely even though the aperture doesn't close at all.

QuoteOriginally posted by audiobomber Quote
No, it doesn't. I just tried it. In Av mode, I set the aperture on my Kiron 28mm f2 manual lens to f2.0 and ISO to 400, and took a photo. Shutter speed was 1/45s. Then I set the aperture to f22 and took the photo again. Same result, the shutter speed remained at 1/45s and the exposure didn't change. Which means both photos were taken with the aperture fully open. The lens does not stop down in Av mode.
Yes the lens doesn't stop down. Any K-lens (non-A) works only wide open in Av. But manual/preset M42 lenses are stopped down straight from the aperture ring and that's what I was referring to with that Helios-44. In Av I just stop the lens down from the aperture ring and the body "sees" the lightlevel decreasing and adjusts the shutter speed accordingly.

There is differences with these M42 lenses though. Helios-44 is so narrow from the mount that it doesn't cover/short the electric contacts of the mount and this results in underexposure in Av. If you use a fatter lens which shorts the contacts the exposure is closer to correct. Usually all M/K-lenses have a wide chrome mount which shorts the contacts and this results in somewhat correct exposures (but only wide open)

edit: I see you edited your post, but I hope my post still answers you question.
11-01-2010, 11:43 AM   #10
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Actually it seems that in Av mode the k-x briefly closes the aperture to the ring setting with an M-lens, but still manages expose with it fully open. The aperture can be seen closing trough the lens, but the actual exposure is apparently fully open. After seeing the aperture closing I assumed it would have done this for exposure ... pretty strange :-o
11-01-2010, 11:44 AM   #11
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QuoteOriginally posted by ovim Quote
Yes the lens doesn't stop down. Any K-lens (non-A) works only wide open in Av. But manual/preset M42 lenses are stopped down straight from the aperture ring and that's what I was referring to with that Helios-44. In Av I just stop the lens down from the aperture ring and the body "sees" the lightlevel decreasing and adjusts the shutter speed accordingly.
Yes, it does answer my question, thanks. So I guess that means that you are also trying to focus through the reduced aperture with a screw-mount lens? I have enough trouble already, manually focussing through a wide open aperture.
11-01-2010, 11:56 AM   #12
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QuoteOriginally posted by ovim Quote
K-X users on this thread seem to disagree with you about the mirror moving when metering with the green button. In my K-r I can also clearly hear/see the mirror flipping, even with a M-lens set to it's largest aperture the viewfinder briefly blacks out completely even though the aperture doesn't close at all.
...
Well, they are right to disagree. I tried this without a lens to better see the mirror assuming it would be the same as with an M-lens mounted and it stayed put. With the lens mounted I can see the mirror going up trough the lens so it being there makes a difference.
11-01-2010, 11:59 AM   #13
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QuoteOriginally posted by audiobomber Quote
Yes, it does answer my question, thanks. So I guess that means that you are also trying to focus through the reduced aperture with a screw-mount lens? I have enough trouble already, manually focussing through a wide open aperture.
Thats right, but it can be done in good light. Or you can focus first and then close the aperture.

QuoteOriginally posted by jolepp Quote
Well, they are right to disagree. I tried this without a lens to better see the mirror assuming it would be the same as with an M-lens mounted and it stayed put. With the lens mounted I can see the mirror going up trough the lens so it being there makes a difference.
I noticed the same thing, it doesn't do anything if the lens is not mounted. Does your K-x work the same way as K-r with M42 lenses: no sound, just the shutter speed changes?
11-01-2010, 03:03 PM   #14
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QuoteOriginally posted by ovim Quote
...
I noticed the same thing, it doesn't do anything if the lens is not mounted. Does your K-x work the same way as K-r with M42 lenses: no sound, just the shutter speed changes?
That is what it does, yes. Both I've are of the variety that is not likely to short the mount contacts: there is a black coating on the lens mount flange.

I've been trying to figure out the hows and whys of the aperture control and thought I had it pretty much covered, but it seems there are new mysteries here:

Why lift the mirror with the green button?

Why not without the contacts being shorted out?

Why the apparently superfluous aperture lever operation in Av mode (with an M lens)?

I suppose incorrectly nitpicking here was a good thing as far as not running out things to ponder ;-)
11-01-2010, 03:20 PM   #15
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QuoteOriginally posted by ovim Quote
....... I'm so used to the K200D "closing" the aperture even with M42 lenses that first I thought nothing happened when I pressed the button....
wouldn't have thought the K200D or any other Pentax dslr
stops down the aperture of M42 len. The only aperture movement is via the human finger surely.

Pete
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