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12-25-2012, 08:36 PM   #1
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K-o1 Manual Mode Phantom light meter?

Hello all,

I am just starting to put the k-o1 through its paces in manual mode. I have noticed a few things that I am not sure how to account for. I am 99% certain this is user error and was hoping someone had some suggestions. As I have scanned the forum and have not seen anything dealing with this particular issue, I will try to present my question as clearly as possible.

When using M mode with the following lenses/settings, I cannot seem to consistently make the light meter appear at the bottom of the screen. Also, FW version is 1.01, recently updated. Also, I do not have autoISO set for any of these tests):

40mm XS 2.8: M mode: Man Focus enabled: Set ISO (not auto ISO). Can toggle f-stop and exposure time and see changes reflected in light meter.
TAIR 11A 135mm -- M mode: Manual Focus: Can change ISO, Shutter Speed and see changes reflected in light meter.
PENTAX-M SMC 50mm f1.7 -- M mode. Can change ISO, can perform DOF/Meter preview (can hear lens stop-down), can change shutter speed, no light meter showing up at bottom.
Phoenix 17-35mm manual focus lens: same as above. No light meter showing up.
K-mart FOCAL 28mm f/2.8 -- same as above. No light meter showing up.

I am not sure what it is that I did wrong because i cannot recall changing any settings in between lens swaps today. I also just re-read the manual from front to back and cannot seem to find anything about this.

Please advise if anyone can assist. Trying to stop-down meter without a meter in your display is a little frustrating!

Thanks for your assistance!

Greg

12-25-2012, 09:47 PM   #2
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Also,

Just reproduced the same results. The TAIR 11a and the 40mm f/2.8 XS displayed the light meter, others did not. Also, it may be worth mentioning that the TAIR 11a that I have (just received for xmas) is fitted with a Tamron Adaptall 2. Further, when I stop down with the TAIR, the K-o1 responds almost exactly like a film SLR -- viewfinder dims, exp and ISO HUD flash red -- it appears that I am getting a real-time look at DOF and exposure preview with no need for stopping down to meter? The TAIR doesnt have a lever and it has two aperture rings -- 1 stopped, one non-stopped. Dont know what the deal is. If anyone can reproduce this and let me know if there are any problems with my settings or something, I'd greatly appreciate it!!

Thanks again!

Greg
12-26-2012, 12:32 AM - 1 Like   #3
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I maybe wrong but I think you need to mount a KA (or A lens -- similar to the other Pentax DSLR) to be able to use the meter, else you use the green button for the camera to meter the scene. I am not sure whats with the Tair communicating with the body
12-26-2012, 04:18 PM   #4
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QuoteOriginally posted by Salagubang Quote
I maybe wrong but I think you need to mount a KA (or A lens -- similar to the other Pentax DSLR) to be able to use the meter, else you use the green button for the camera to meter the scene. I am not sure whats with the Tair communicating with the body
See, that's the thing: The TAIR has no possible way of communicating with the body whatsoever. Its just plain a metal adaptall that has been somewhat permanently affixed to the M42 screwmount. Also, I tried the 17-35 Phoenix again, which does have an "A" setting. Bingo. The light meter came on. This probably accounts for some of it, but with the TAIR communicating, I cannot account for it other than, like I said above -- dual aperture rings, one stopped, the other not -- maybe the fact that it has a un-stopped aperture diaphragm (which wouldnt make sense either, because I thought that data concerning autofocus and aperture settings were communicated at the point of contact in the lens mount). In any case, I am going to continue to try out other lenses and present my findings -- which may amount to "the Ghost of Lenin haunts the TAIR 11a!!" Thanks for the tip on the "A" setting!!

12-26-2012, 06:49 PM - 1 Like   #5
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The K-01 handles M42, K/M, and A lenses slightly differently. I think it goes back to the "crippled" mount not being able to detect the range of apertures, combined with trying to hold the aperture on K/M lenses wide open for focusing. The Adaptall must be insulated enough that the K-01 doesn't detect it like a K/M even though it's a metal mount. In some ways, the M42 is more convenient, because like you said, it works like an old film camera. I'm guessing that it's displaying the "Phantom meter" on the A lens because while it holds the aperture open, it knows the range of f-stops, and on the M42 because it just meters available light, but not the K/M lenses because it's holding the aperture open but doesn't know what the lens can do. In some ways, the M42 is more convenient than the K/M. I put a little celophane tape on the mount of a couple of my M lenses so that they act like M42s.
12-26-2012, 09:58 PM   #6
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Thanks!! Can you elaborate a little on the tape thing. I had seen this mentioned in passing, but am still a bit fuzzy about where to place the tape. I think I'd like to give this a try. Thanks again for pointing me in the right direction
12-26-2012, 10:26 PM   #7
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See here for details:

Making an M lens automatic, sort of. | Flickr

12-27-2012, 01:46 PM   #8
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THoog,when you use the tape on your lenses, does the auto iso value change or only the shutter speed value? I only see the shutter speed change, The ISO value stays at the highest setting that i've set. Have you found a way to keep the sutter speed set and have the ISO value change?

Rick

12-27-2012, 03:19 PM   #9
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Well, the K-01 seems to prefer to push the ISO as high as it can (maybe biased towards faster shutter speeds?), but the behavior definitely depends on the lighting setup. Sometimes it seems to go out of its way to shoot at 1/125. What I usually do is dial the highest ISO down to what I think is "reasonable", let it meter, then use exposure compensation (<+/-> button and thumbwheel) for more control over the shutter speed. If that just won't give me something I like, there's always manual ISO and Green Button metering.

It would have been nice if they had allowed us to adjust the lower end of the ISO range ISO as well as upper, (I think the K-5 does, using both wheels), but I understand leaving some features out as an incentive to upgrade to the top-o-the-line.

-Todd
12-27-2012, 03:58 PM   #10
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Thanks Tood, I did not think there was a way to make TAv work like how I discribed with the M series of lenses.

Rick
12-28-2012, 09:52 PM   #11
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I was looking at the TAIR again today. I dont know if this is something inherent to the design of that particular lens, or the mount adapter that was already on it when I received it (it was a used lens. The adapter rings seems to have a very small screw/pin holding it in place). Apparently at the very end of the lens there is a little recessed lip that prevents the TAIR from contacting ANY of the electronic contacts on the ring of the K-mount (on the camera, that is). It is basically floating in the mount. It wont click in either. I tried it on my wife's K-10D and the same thing, so it is definitely not a K-o1 thing. Now, I have been shooting with this for the past two days, just putting it through its paces at the wide end of the aperture range (and getting myself used to composing an image at that focal legnth....phew!) and I know that the TAIR has a reputation for being a tad 'soft' anyway, but I have also read some other forum entries about the K-o1 and the 40mm XS ....something about not being clicked in all the way causing soft focus. Also of concern is that it cannot seem (with this lens mount adapter anyway) to lock into the mount and it is very possible to remove the lens, not only without depressing the release button, but in some cases while focusing. Perhaps this is a lens specific question about the TAIR 11A 135mm f/2.8, so if this is off topic, please advise. In any case, is this normal behavior out of this lens/adapter &/or adapted M42 lenses in general? As long as I am sure I am getting out of the lens what it is capable of, I can take precautions when handling it --- my main thing is can the lens go sharper or is the loose seating in the mount causing focal problems?
12-28-2012, 11:21 PM   #12
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I haven't used that adapter, but softness isn't a problem for M42 lenses in general. I've got Zeiss and Takumar M42s on various adapters that are razor sharp. From your description, I wouldn't be surprised if the lens had problems focusing to infinity - that's a common problem if the adapter is too thick and the rear of the lens isn't flush with the mount. If it is still soft at shorter ranges, try stopping down to see if it improves. If it is STILL soft, it's probably the lens.

The issue with the 40 XS is different - when the lens isn't correctly aligned (locked in), the screw drive can't engage properly and it's lucky to focus at all - like trying to turn a doorknob with butter on your hands.
12-29-2012, 07:08 PM   #13
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THoog -- just tried the cellophane tape w/the 5omm. Awesome. Works exactly like the TAIR was working now. That's it. I do have a few more questions.

Messing around with stop-down metering.
I have the red button mapped to: PREVIEW
I have the green button mapped to adjust exposure (I think -- in M/TAv mode sets shutter with fixed aperture to adjust exposure)
I stop down, I press the red button to check DOF. Focus. Press green button. I can see it adjust the length of the exposure. I take the picture. It is grossly underexposed by. Finding I need an exposure of 100% or more longer than what I am getting. This is without the auto ISO enabled. Now, I will say that I am using very long 15" to 30" exposures and low ISO (100 and 200). Any ideas as to what is happening?

Finally -- thanks so much for helping me understand how the camera deals with the different types of lenses and that this has to do with the contact at the mount. I will let you know about that TAIR after I have had some sunny days to stop down, Also, these were taken with the TAIR wide open on an overcast day. I suppose I am not sure how to qualify the 'softness' of this. Maybe the lens is more 'painterly' than 'soft?' I dont know. Is this an acceptable sharpness for a 135mm at f/2.8?
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12-30-2012, 07:48 AM   #14
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QuoteOriginally posted by cristigj Quote
THoog -- just tried the cellophane tape w/the 5omm. Awesome. Works exactly like the TAIR was working now. That's it. I do have a few more questions.

Messing around with stop-down metering.
I have the red button mapped to: PREVIEW
I have the green button mapped to adjust exposure (I think -- in M/TAv mode sets shutter with fixed aperture to adjust exposure)
I stop down, I press the red button to check DOF. Focus. Press green button. I can see it adjust the length of the exposure. I take the picture. It is grossly underexposed by. Finding I need an exposure of 100% or more longer than what I am getting. This is without the auto ISO enabled. Now, I will say that I am using very long 15" to 30" exposures and low ISO (100 and 200). Any ideas as to what is happening?

Finally -- thanks so much for helping me understand how the camera deals with the different types of lenses and that this has to do with the contact at the mount. I will let you know about that TAIR after I have had some sunny days to stop down, Also, these were taken with the TAIR wide open on an overcast day. I suppose I am not sure how to qualify the 'softness' of this. Maybe the lens is more 'painterly' than 'soft?' I dont know. Is this an acceptable sharpness for a 135mm at f/2.8?
Hmm... I can't give a definitive answer, except to say I've usually had do trial-and-error myself on long exposures. It's probably something like the camera is calculating a linear solution, when it's really a curve and the errors show up at the extreme ends.

I don't see anything wrong with sharpness on those shots - they look fine, especially if the TAIR was wide-open. Nice pix! 'Painterly' is a good word - I've seen 'soft' lenses described as 'dreamy' or 'romantic'. Unless you need to do big prints or heavy cropping, sharpness isn't that big a deal (except to the pixel-peepers).
12-30-2012, 09:18 AM   #15
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gotcha. It seemed to be wanting to default to 13 seconds (?) regardless of where I set the f-stop. I was a painting major in college, this lens somewhat reminded me of the way Renaissance painters rendered fabrics. Looks like we have some sun today. I am going to try to get out and see what this thing does stopped down a little. Thanks so much THoog! I appreciate all the input!
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