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04-11-2011, 10:46 AM   #16
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QuoteOriginally posted by glee46 Quote
I was doing sunsets last night & on my K20D with a 35mm f/3.5 M42, the metering was way off. I switched over to spot, and no problem.
Given the nature of the spot metering light-path design, I'm not surprised you had success with that exposure. Everything was pretty much the same light value over the whole image so few highlights were affected by the split prism to affect the overall exposure. When there is a wide range of light values in the center area of the VF the exposure is more subject to "miss-interpretation" due to scattering.

In a related sense, a significant difference between center weighted and mosaic metering is the ability to logically de-value extreme light values in less significant areas of the metering pattern rather than integrating all values equally or based solely on a weighted average over the entire scene.

In an overly simplistic explanation, the split prism screen, through various modes of internal refraction and reflection in the VF can muddle up the exposure in unpredictable ways and can cause a more sensitively response to varying lens aperture and FL than an averaging metering scheme.

H2

04-11-2011, 10:53 AM   #17
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QuoteOriginally posted by pacerr Quote
Given the nature of the spot metering light-path design, I'm not surprised you had success with that exposure. Everything was pretty much the same light value over the whole image so few highlights were affected by the split prism to affect the overall exposure. When there is a wide range of light values in the center area of the VF the exposure is more subject to "miss-interpretation" due to scattering.

In a related sense, a significant difference between center weighted and mosaic metering is the ability to logically de-value extreme light values in less significant areas of the metering pattern rather than integrating all values equally or based solely on a weighted average over the entire scene.

In an overly simplistic explanation, the split prism screen, through various modes of internal refraction and reflection in the VF can muddle up the exposure in unpredictable ways and can cause a more sensitively response to varying lens aperture and FL than an averaging metering scheme.

H2
I would agree with all the above, i'd also point out that without seeing the example of the scene we likely can't properly critique technique in any case we can just throw possibilities out there and hope they work for him. we have half the equation his explanation of what happened and how, but exif data and an image is the other half allowing proper technical advice (for all we know it was a scene with greater Dr than the camera could handle and a nd grad filter would have been the answer to correct the exposure to achieve the goal. (it sounds suspiciously like this to me)
there are many times i don't trust my built in metering with any kind of lens and override it based on past experience to achieve the desired effect. Correct Exposure can be pretty fluid

Edit - Blown out white clothes may not be solved by spot metering BTW, if you meter the clothes it will consider them 18% gray not white as meters are based on reading 18% grey. a quick meter of the scene with a grey card on spot or any other metering method would give a more neutral exposure
04-11-2011, 07:18 PM   #18
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QuoteOriginally posted by eddie1960 Quote
I would agree with all the above, i'd also point out that without seeing the example of the scene we likely can't properly critique technique in any case we can just throw possibilities out there and hope they work for him. we have half the equation his explanation of what happened and how, but exif data and an image is the other half allowing proper technical advice (for all we know it was a scene with greater Dr than the camera could handle and a nd grad filter would have been the answer to correct the exposure to achieve the goal. (it sounds suspiciously like this to me)
there are many times i don't trust my built in metering with any kind of lens and override it based on past experience to achieve the desired effect. Correct Exposure can be pretty fluid

Edit - Blown out white clothes may not be solved by spot metering BTW, if you meter the clothes it will consider them 18% gray not white as meters are based on reading 18% grey. a quick meter of the scene with a grey card on spot or any other metering method would give a more neutral exposure
I took a look at the exif data of the shots I took. There is one setting which could have made a difference. The white balance was set to daylight.


This was one of three I used to bracket the shot I posted here yesterday. I think you can see the exif data from it.

So, it very well could have been my problem, but the spot did allow me to get my shots.
04-11-2011, 08:23 PM   #19
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QuoteOriginally posted by DogLover Quote
B&H has a few. Try this: pentax focus screen
First place I checked, but no luck. Those are optional screens for the K10D and K20D. What you want is LL-60, LI-60 screens that was installed or was available as optional accessory to the 1stDS digital SLR. I couldn't find the screen anywhere, I looked up tom1803, a Marketplace Reseller who from time to time has some brand new Pentax F1.7x AF TC for sale, and asked him if he could locate one. I have just placed an order from tom1803 for an LL-60. Hopefully, it won't be too long before I receive it.

Thanks,

04-11-2011, 08:33 PM   #20
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QuoteOriginally posted by excanonfd Quote
First place I checked, but no luck. Those are optional screens for the K10D and K20D. What you want is LL-60, LI-60 screens that was installed or was available as optional accessory to the 1stDS digital SLR. I couldn't find the screen anywhere, I looked up tom1803, a Marketplace Reseller who from time to time has some brand new Pentax F1.7x AF TC for sale, and asked him if he could locate one. I have just placed an order from tom1803 for an LL-60. Hopefully, it won't be too long before I receive it.

Thanks,
Well, they do show 3 different "60" models that fit the K7 (and therefore, the K5).
04-11-2011, 09:01 PM   #21
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QuoteOriginally posted by DogLover Quote
Well, they do show 3 different "60" models that fit the K7 (and therefore, the K5).
Yes, they do but if you read SOldBear's second reply in the thread, installing an LL-60 or LI-60 in a K10D or K20D will allow for more accurate metering with MF lenses, but that he has not found a workaround for a K7. If installing an optional K7 screen gives better metering than the standard screen, it wouldn't be much of a workaround.

Thanks,
04-12-2011, 07:31 AM   #22
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QuoteOriginally posted by DogLover Quote
Well, they do show 3 different "60" models that fit the K7 (and therefore, the K5).
I checked everywhere as well for the LL-60, LI-60. No where to be found.

Here's what works for me. Shoot. Look at the screen and adjust.
My biggest problem is forgetting to set the White Balance when I'm going from outside to inside.

I think part of what makes these old lenses great to have is getting to know them. Seeing where they work best, and doing everything to manual.

I've been shooting with a 35mm f/3.5 M42 for over a week, on my K20D. To me, it's more fun then my new K5 with a Tamron 28-75mm f/2.8.

In fact, I hardly use the AF on it due to using the manual focus so much with my older lenses.
04-12-2011, 09:27 AM   #23
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QuoteOriginally posted by pacerr Quote
Given the nature of the spot metering light-path design, I'm not surprised you had success with that exposure. Everything was pretty much the same light value over the whole image so few highlights were affected by the split prism to affect the overall exposure. When there is a wide range of light values in the center area of the VF the exposure is more subject to "miss-interpretation" due to scattering.

In a related sense, a significant difference between center weighted and mosaic metering is the ability to logically de-value extreme light values in less significant areas of the metering pattern rather than integrating all values equally or based solely on a weighted average over the entire scene.

In an overly simplistic explanation, the split prism screen, through various modes of internal refraction and reflection in the VF can muddle up the exposure in unpredictable ways and can cause a more sensitively response to varying lens aperture and FL than an averaging metering scheme.

H2
QuoteOriginally posted by eddie1960 Quote
I would agree with all the above, i'd also point out that without seeing the example of the scene we likely can't properly critique technique in any case we can just throw possibilities out there and hope they work for him. we have half the equation his explanation of what happened and how, but exif data and an image is the other half allowing proper technical advice (for all we know it was a scene with greater Dr than the camera could handle and a nd grad filter would have been the answer to correct the exposure to achieve the goal. (it sounds suspiciously like this to me)
there are many times i don't trust my built in metering with any kind of lens and override it based on past experience to achieve the desired effect. Correct Exposure can be pretty fluid

Edit - Blown out white clothes may not be solved by spot metering BTW, if you meter the clothes it will consider them 18% gray not white as meters are based on reading 18% grey. a quick meter of the scene with a grey card on spot or any other metering method would give a more neutral exposure
just to comment on this discussion, i happened to be looking at a D7000 manual, and the metering curves. They have a note that any metering cell that shows more than 16.3 EV is interpreted by matrix metering to be 16.3 ev. that eliminates considering the sun as a correct exposure.

Spot metering may also be, along with the sometimes high exposuyre compensation needs for M42 lenses, the reason the photo worked. It was not the accuracy of spot metering as much as offsetting errors

04-12-2011, 09:30 AM   #24
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QuoteOriginally posted by glee46 Quote
I checked everywhere as well for the LL-60, LI-60. No where to be found.

Here's what works for me. Shoot. Look at the screen and adjust.
My biggest problem is forgetting to set the White Balance when I'm going from outside to inside.

I think part of what makes these old lenses great to have is getting to know them. Seeing where they work best, and doing everything to manual.

I've been shooting with a 35mm f/3.5 M42 for over a week, on my K20D. To me, it's more fun then my new K5 with a Tamron 28-75mm f/2.8.

In fact, I hardly use the AF on it due to using the manual focus so much with my older lenses.
there have to be a ton of these screens about, either in old discarded *istD's or where people have changed out the screen for a split image.

Note, however, once you pur an LL60 screen into a K10/20, there may be some unpredictable results on A mount or later lenses, because the camera will be applying a correcting factor that is no longer needed, I would anticipate, (although I never tried when I tested the *istD screen in my K10D) that you would need a permenant but different EV comp for each different maximum aperture lens you owned.

this becomes a double edged sward for the K10D where there is no EV comp in manual mode.
04-12-2011, 11:20 AM   #25
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QuoteOriginally posted by Lowell Goudge Quote
Note, however, once you pur an LL60 screen into a K10/20, there may be some unpredictable results on A mount or later lenses, because the camera will be applying a correcting factor that is no longer needed, I would anticipate, (although I never tried when I tested the *istD screen in my K10D) that you would need a permenant but different EV comp for each different maximum aperture lens you owned.

this becomes a double edged sward for the K10D where there is no EV comp in manual mode.
I have two copies of K10D, both having LL-60 screen.

About "unpredictable results," I haven't been able to find any perceptible problem in metering with A and later lenses. In fact, most of my often-used lenses are autofocus lenses (see signature below). The only manual lens in the list is the Vivitar close-focus 135mm 1:2.8.

Last edited by SOldBear; 04-12-2011 at 10:28 PM.
04-12-2011, 09:33 PM   #26
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If they're Super taks, then no they won't have the A contacts. I don't own Super Taks, but I suspect they act very similarly to adapted lenses (I have several Leica R mount lenses adapted to Pentax K mount). That is, they will support spot metering.

If you meter off the highlights, you may put your exposure to the subject too dark. White clothing can be difficult to deal with, even in overcast/cloudy conditions because it reflects so much light.

Keep shooting and keep at it! It's very hard to know what could have been done to improve your pictures without seeing them, but have a look at fill flash to see if it may help.

QuoteOriginally posted by justtakingpics Quote
I don't know. They are super tak m42 lenses. All i know is that one part was blown out and didn't know if I could have metered off of that one part. In reality the picture isn't horrible. i think I was just getting to technical and critical that anything "off" in the image was driving me crazy.

Most of my images have been terrible, mostly because of the photographer. I just keep moving the wheel to different shutter speeds based upon the histogram and what I can see of the image on the LCD. Sometimes I get the DOF wrong and sometimes I don't get my subject to lift their chin, the light isn't right (or I can't tell for sure), and so on....sorry for the rant and thanks.
11-10-2011, 12:20 PM   #27
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QuoteOriginally posted by Lowell Goudge Quote
there have to be a ton of these screens about, either in old discarded *istD's or where people have changed out the screen for a split image.
Note, however, once you put an LL60 screen into a K10/20, there may be some unpredictable results on A mount or later lenses, because the camera will be applying a correcting factor that is no longer needed, I would anticipate, (although I never tried when I tested the *istD screen in my K10D) that you would need a permenant but different EV comp for each different maximum aperture lens you owned.
this becomes a double edged sward for the K10D where there is no EV comp in manual mode.
I use a GX20 with the LL-60 screen. It is now broadly accurate with SMCP-M lenses whereas it was inconsistent with the factory-fitted screen. While it was generally accurate, with occasional underexposure with the DA 16-45mm f4.0, it now underexposes fairly consistently and an exposure compensation of +0.7 EV usually gives a satisfactory result. Sometimes compensation of up to +1.3 EV is necessary to get the desired result but I have not done systematic tests in order to pin down the circumstances where additional compensation is required. I am reviving this old thread because I could not find a thread where the behaviour of the LL-60 screen with both manual and electronic lenses is discussed together.
11-10-2011, 12:47 PM   #28
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QuoteOriginally posted by chhayanat Quote
I use a GX20 with the LL-60 screen. It is now broadly accurate with SMCP-M lenses whereas it was inconsistent with the factory-fitted screen. While it was generally accurate, with occasional underexposure with the DA 16-45mm f4.0, it now underexposes fairly consistently and an exposure compensation of +0.7 EV usually gives a satisfactory result. Sometimes compensation of up to +1.3 EV is necessary to get the desired result but I have not done systematic tests in order to pin down the circumstances where additional compensation is required. I am reviving this old thread because I could not find a thread where the behaviour of the LL-60 screen with both manual and electronic lenses is discussed together.
I think due to the metering on the K10D and K20D and the samsung GX20 as well, there is a 'fudge factor" applied to lenses that are not F5.6, to corrrect for the variation of metering as a function of aperture (as I measured with my K50/1.4) and as a result, when you put the LL-60 screen in place, while manual lenses now meter nicely, A lenses are getting the "fudge factor" applied when they no longer need it. ALthough this makes A lenses require an exposure compensation, since all metering is done wide open, a single factor is now needed for each lens, as opposed to a varing factor for each manual lens as a fucntion of selected aperture. this is a lot easier to deal with in the field in my opinion
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