Manual Lens Problems on the K10D

Kemal · 02-22-2007, 09:22 AM

This is extremely annoying. I picked up the K10D in the hopes of using some great manual Pentax lenses I have, only to find there are exposure problems and things are not metering well because the camera doesnt know what f-stop the lens is at in M mode.

I called Pentax about it and that was fruitless.

Is this a solution? I was reading on the Pentaxuser UK forum that if you use the DOF(shutter preview?) button connected to the on/off switch and read the EV bar in the viewfinder and use the scroll button to reach the center of the bar then take a picture of your subject...would that work in making a good exposure using a manual lens?

I tried it out and the exposures were better than using the green button, but I can't inspect them on a screen right now and the histogram is sitting on the fence in showing a proper exposure.

I don't want to buy new lenses and this camera was advertised as being able to be backwards compatible with manual lenses. How could they have overlooked this? Short of a new firmware or focus screen switch- has anyone had success in using manual lenses properly?

Last edited by Kemal; 02-22-2007 at 09:53 AM.

borno · 02-22-2007, 10:07 AM

Hi kemal,
I've got the same thing going on, I get the same result with the green button or depth of field preview. Mine overexposes about 1.5 stops (unless wide open) so I take a reading and turn the shutter wheel 2 or 3 "clicks" faster and take a shot then check the histogram, PIA but it's closer than what the camera is saying. If a focusing screen would fix it that would be great, but I want to know for sure.( that would make everything...groovy...)
tom b

Denis · 02-22-2007, 10:24 AM

Originally posted by Kemal

This is extremely annoying. I picked up the K10D in the hopes of using some great manual Pentax lenses I have, only to find there are exposure problems and things are not metering well because the camera doesnt know what f-stop the lens is at in M mode.

I called Pentax about it and that was fruitless.

Is this a solution? I was reading on the Pentaxuser UK forum that if you use the DPOF button by the on/off switch and read the EV bar and use the scroll button to reach the center of the bar then take a picture of your subject...would that work in make a good exposure using a manual lens?

I tried it out and the exposures were better than using the green button, but I can't inspect them on a screen right now and the histogram is sitting on the fence in showing a proper exposure.

I don't want to buy new lenses and this camera was advertised as being able to be backwards compatible with manual lenses. How could they have overlooked this? Short of a new firmware or focus screen switch- has anyone had success in using manual lenses properly?

I have use manual lenses successfully. First make sure that that "use aperture ring" is on in the "C" menu. If your lens has "A" function, it is not the same issue.
Select manual focusing (below RAW button) on front of camera and select "M" on top dial. Frame, manually focus (green indicator and beep if focused) and set desired aperture for DOF, press green button to see camera exposure speed. If shutter speed to low either increase ISO or aperture and press green button to see new speed. On the other hand you can use front dial to change shutter speed but this will change the image to darker or brighter. If happy. snap image.

It took me about a minute to change to a manual lens, 50mm f1.7, change ISO and WB , switch to manual mode and take a picture.

It is very close to a manual camera but instead of instant feedback from a light sensor which require to manually change speed or aperture, the green button set your shutter speed based on your settings, aperture and ISO. You have to make a decision to either change ISO or aperture to achieve the desired image results if you are not happy with speed, i.e too slow. Always press the green button to see the shutter speed prior to taking an image is a good habit unless you desire to change the shutter speed using the front dial to adjust brightness, pressing the green button after that would simply reset speed. Hope this help.

borno · 02-22-2007, 11:12 AM

the issue is inaccurate metering in some cases, for example my 50mm f1.4 in "a" mode may give me 1/20 s at f8 iso400 and if I use the aperture ring at f8 the camera gives me 1/8 sec. and the overexposure is consistant and repeatable for other lenses.
tom

Kemal · 02-22-2007, 11:58 AM

Well, I can shoot fine in Tav mode, Av & Tv mode with a manual lens. Just M seems to be hit or miss. I'm using a 55 mm lens that came with a Pentax KX from 1975.

gorfmai · 02-22-2007, 01:34 PM

Originally posted by Kemal

Well, I can shoot fine in Tav mode, Av & Tv mode with a manual lens. Just M seems to be hit or miss. I'm using a 55 mm lens that came with a Pentax KX from 1975.

A KX? wow, haven't heard that in ages...

borno · 02-22-2007, 03:12 PM

I think M mode is hit or miss because it is the only mode that lets the lens stop down to your chosen f-stop, other modes default to av and use the lens wide open. Thats what the manual says anyway pg.210
hope this helps
tb

Kemal · 02-22-2007, 03:20 PM

Yeah, but I'm using a fully manual lens. Not a newer lens with contacts that would tell the camera what f-stop it's at. I move the aperture ring to both f 1.4 and f22 and get good exposures.

MPrince · 02-22-2007, 05:02 PM

I have a K100D, not a K10D, and currently have 2 manual lenses. My SMC Pentax-M 1:1.4 50mm is dead-on accurate most of the time. I just received today a SMC Pentax-M1:3.5 135mm lens. Haven't had time yet to put it through its paces, but it looks like it underexposes a little bit. Easy enough to compensate for.

So unless you have a seriously out-of-whack problem, I think it's just a matter of getting to know your lenses and how they perform with your camera, and making the necessary EV adjustments.

And yes, the DOF preview method seems to be more accurate than the AE/L button. (I guess that's the green button on the K10D).

**Lowell Goudge** · 02-23-2007, 02:11 PM

to all on this thread note.

K10D like *istD meters when you have set the custom function to use manual lenses, and then functionality is restricted as follows:

In AV mode it shoots at full apature but does set shutter correctly for full apature

in M mode you press the green button next to shutter release and it sets the shutter for correct lens apature (you will notice it stops the lens down for an instant in this procees)

The metering otherwise does not do anything. Note also P-TTL does not work with non "A" lenses. (on *istD, TTL flash works fine with K mounts)

If you have a pentax "A" lens, all functions work.

jthommo · 02-23-2007, 02:19 PM

This is a problem that has been discussed ad nauseum on dpr. It seems that some K10Ds exhibit the problem - and some don't. I've tested throughout the aperture range on mine and its OK, (and its fine in day to day use) but others find it is extremely inaccurate in the mid ranges. I have no idea what the cause - or a fix - might be....but it is driving some dpr people nuts.

Photomy · 02-23-2007, 02:57 PM

Originally posted by Kemal

Yeah, but I'm using a fully manual lens. Not a newer lens with contacts that would tell the camera what f-stop it's at. I move the aperture ring to both f 1.4 and f22 and get good exposures.

I do not believe that lens information is needed if you operate as a fully manual lens including metering while stopped down. Just use M mode and be sure you meter while stopped down using green button (as others have said). No reason not to work since the stopped down position is the position the photo will be taken at.

02-22-2007, 09:22 AM	#1
Kemal Forum Member Join Date: Dec 2006 Posts: 78	Manual Lens Problems on the K10D This is extremely annoying. I picked up the K10D in the hopes of using some great manual Pentax lenses I have, only to find there are exposure problems and things are not metering well because the camera doesnt know what f-stop the lens is at in M mode. I called Pentax about it and that was fruitless. Is this a solution? I was reading on the Pentaxuser UK forum that if you use the DOF(shutter preview?) button connected to the on/off switch and read the EV bar in the viewfinder and use the scroll button to reach the center of the bar then take a picture of your subject...would that work in making a good exposure using a manual lens? I tried it out and the exposures were better than using the green button, but I can't inspect them on a screen right now and the histogram is sitting on the fence in showing a proper exposure. I don't want to buy new lenses and this camera was advertised as being able to be backwards compatible with manual lenses. How could they have overlooked this? Short of a new firmware or focus screen switch- has anyone had success in using manual lenses properly? Last edited by Kemal; 02-22-2007 at 09:53 AM.

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02-22-2007, 10:07 AM	#2
borno Veteran Member Join Date: Nov 2006 Location: md-usa Photos: Gallery \| Albums Posts: 2,580	Hi kemal, I've got the same thing going on, I get the same result with the green button or depth of field preview. Mine overexposes about 1.5 stops (unless wide open) so I take a reading and turn the shutter wheel 2 or 3 "clicks" faster and take a shot then check the histogram, PIA but it's closer than what the camera is saying. If a focusing screen would fix it that would be great, but I want to know for sure.( that would make everything...groovy...) tom b

02-22-2007, 10:24 AM	#3
Denis Veteran Member Join Date: Jan 2007 Location: St-Albert, Alberta, Canada Posts: 330	Originally posted by Kemal This is extremely annoying. I picked up the K10D in the hopes of using some great manual Pentax lenses I have, only to find there are exposure problems and things are not metering well because the camera doesnt know what f-stop the lens is at in M mode. I called Pentax about it and that was fruitless. Is this a solution? I was reading on the Pentaxuser UK forum that if you use the DPOF button by the on/off switch and read the EV bar and use the scroll button to reach the center of the bar then take a picture of your subject...would that work in make a good exposure using a manual lens? I tried it out and the exposures were better than using the green button, but I can't inspect them on a screen right now and the histogram is sitting on the fence in showing a proper exposure. I don't want to buy new lenses and this camera was advertised as being able to be backwards compatible with manual lenses. How could they have overlooked this? Short of a new firmware or focus screen switch- has anyone had success in using manual lenses properly? I have use manual lenses successfully. First make sure that that "use aperture ring" is on in the "C" menu. If your lens has "A" function, it is not the same issue. Select manual focusing (below RAW button) on front of camera and select "M" on top dial. Frame, manually focus (green indicator and beep if focused) and set desired aperture for DOF, press green button to see camera exposure speed. If shutter speed to low either increase ISO or aperture and press green button to see new speed. On the other hand you can use front dial to change shutter speed but this will change the image to darker or brighter. If happy. snap image. It took me about a minute to change to a manual lens, 50mm f1.7, change ISO and WB , switch to manual mode and take a picture. It is very close to a manual camera but instead of instant feedback from a light sensor which require to manually change speed or aperture, the green button set your shutter speed based on your settings, aperture and ISO. You have to make a decision to either change ISO or aperture to achieve the desired image results if you are not happy with speed, i.e too slow. Always press the green button to see the shutter speed prior to taking an image is a good habit unless you desire to change the shutter speed using the front dial to adjust brightness, pressing the green button after that would simply reset speed. Hope this help.

02-22-2007, 11:12 AM	#4
borno Veteran Member Join Date: Nov 2006 Location: md-usa Photos: Gallery \| Albums Posts: 2,580	the issue is inaccurate metering in some cases, for example my 50mm f1.4 in "a" mode may give me 1/20 s at f8 iso400 and if I use the aperture ring at f8 the camera gives me 1/8 sec. and the overexposure is consistant and repeatable for other lenses. tom

02-22-2007, 11:58 AM	#5
Kemal Forum Member Join Date: Dec 2006 Posts: 78 Original Poster	Well, I can shoot fine in Tav mode, Av & Tv mode with a manual lens. Just M seems to be hit or miss. I'm using a 55 mm lens that came with a Pentax KX from 1975.

02-22-2007, 01:34 PM	#6
gorfmai Forum Member Join Date: Jan 2007 Location: NJ USA Photos: Gallery Posts: 51	Originally posted by Kemal Well, I can shoot fine in Tav mode, Av & Tv mode with a manual lens. Just M seems to be hit or miss. I'm using a 55 mm lens that came with a Pentax KX from 1975. A KX? wow, haven't heard that in ages...

02-22-2007, 03:12 PM	#7
borno Veteran Member Join Date: Nov 2006 Location: md-usa Photos: Gallery \| Albums Posts: 2,580	I think M mode is hit or miss because it is the only mode that lets the lens stop down to your chosen f-stop, other modes default to av and use the lens wide open. Thats what the manual says anyway pg.210 hope this helps tb

02-22-2007, 03:20 PM	#8
Kemal Forum Member Join Date: Dec 2006 Posts: 78 Original Poster	Yeah, but I'm using a fully manual lens. Not a newer lens with contacts that would tell the camera what f-stop it's at. I move the aperture ring to both f 1.4 and f22 and get good exposures.

02-22-2007, 05:02 PM	#9
MPrince Veteran Member Join Date: Sep 2006 Location: WV Posts: 1,495	I have a K100D, not a K10D, and currently have 2 manual lenses. My SMC Pentax-M 1:1.4 50mm is dead-on accurate most of the time. I just received today a SMC Pentax-M1:3.5 135mm lens. Haven't had time yet to put it through its paces, but it looks like it underexposes a little bit. Easy enough to compensate for. So unless you have a seriously out-of-whack problem, I think it's just a matter of getting to know your lenses and how they perform with your camera, and making the necessary EV adjustments. And yes, the DOF preview method seems to be more accurate than the AE/L button. (I guess that's the green button on the K10D).

02-23-2007, 02:11 PM	#10
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	to all on this thread note. K10D like istD meters when you have set the custom function to use manual lenses, and then functionality is restricted as follows: In AV mode it shoots at full apature but does set shutter correctly for full apature in M mode you press the green button next to shutter release and it sets the shutter for correct lens apature (you will notice it stops the lens down for an instant in this procees) The metering otherwise does not do anything. Note also P-TTL does not work with non "A" lenses. (on istD, TTL flash works fine with K mounts) If you have a pentax "A" lens, all functions work.

02-23-2007, 02:19 PM	#11
jthommo Veteran Member Join Date: Sep 2006 Location: Canberra, Australia Photos: Gallery Posts: 338	This is a problem that has been discussed ad nauseum on dpr. It seems that some K10Ds exhibit the problem - and some don't. I've tested throughout the aperture range on mine and its OK, (and its fine in day to day use) but others find it is extremely inaccurate in the mid ranges. I have no idea what the cause - or a fix - might be....but it is driving some dpr people nuts.

02-23-2007, 02:57 PM	#12
Photomy Senior Member Join Date: Jan 2007 Location: Kansas City, MO Posts: 174	Originally posted by Kemal Yeah, but I'm using a fully manual lens. Not a newer lens with contacts that would tell the camera what f-stop it's at. I move the aperture ring to both f 1.4 and f22 and get good exposures. I do not believe that lens information is needed if you operate as a fully manual lens including metering while stopped down. Just use M mode and be sure you meter while stopped down using green button (as others have said). No reason not to work since the stopped down position is the position the photo will be taken at.