What capture mode for non A type manual lenses

*gregmoll* · 07-06-2008, 02:08 AM

Hi,

What capture mode works best on a K100D Super for NON “A” diaphram type manual lenses, be they M42s with the “Auto-Manual” switch and the pin locked up or the SMC Pentax-M types with no “A” setting.

I have always used “M” mode and focused wide open, then stopped down the lens to the f number I wanted, pressed “AE-L” to set the exposure and taken the shot.

This morning I did some tests comparing the results of “M mode and AE-L” versus Av only mode, with camera set to Av one focuses wide open and then stop down the lens and immediately take the shot, I then change the f stop and shoot again, all the pictures are correctly exposed regardless of the f stop. In fact the exposure was better than using the “M AE-L” procedure.

This goes contrary to every thing I have read about using NON A type lenses.

Where am I going wrong :<)

Regards
Greg

Mike Cash · 07-06-2008, 02:24 AM

For M42 lenses, I find Av mode is the way to go.

I find the AE-L button ergonomically awkward enough that I generally don't use M lenses on my K100D.

*gregmoll* · 07-06-2008, 05:22 PM

Thanks Mike, I'm going to use the Av mode and see what happens in real life as against testing mode.

Regards
Greg

Mike Cash · 07-07-2008, 07:56 AM

For your M42 lenses, try taping a bit of aluminum foil across the electrical contacts surrounding the lens mount. It will reduce the amount of +EV correction you have to use to get it to meter correctly.

pschlute · 07-07-2008, 10:41 AM

With the M lenses you can use Av mode BUT all you pictures will be taken at the lens maximum aperture, regardless of what you have set the aperture ring to.

Lowell Goudge · 07-07-2008, 11:03 AM

Mike

For non A lenses, I use manual mode, set the apature and press the green button (you would use the AE-L button, this shoudl stop the lens down and set metering.

Av mode as others have stated only shoots wide open.

Alternatively if you want to use the light meter, use DOF preview, and adjust amnually, this has an advantage that you can deliberately over / under expose

lithos · 07-07-2008, 11:23 AM

You don't have to focus, the stop down, when using M lenses.

I use M mode, set ap, hit AE-L button, and shoot.

Big Dave · 07-07-2008, 11:47 AM

Greg,
With lenses such as the M series with auto-diaphram you need to use manual and Ae-L to get the correct exposure. For lenses without auto-diaphram, you can use either manual/ae-l or AV, since the diaphram remains in the working position with the lens in manual. All of my converted lenses work this way, as well as my Nikkors. Sometimes I need to switch to from AV to manual to correct the exposure.

Dave

Originally Posted by gregmoll

Hi,

What capture mode works best on a K100D Super for NON “A” diaphram type manual lenses, be they M42s with the “Auto-Manual” switch and the pin locked up or the SMC Pentax-M types with no “A” setting.

I have always used “M” mode and focused wide open, then stopped down the lens to the f number I wanted, pressed “AE-L” to set the exposure and taken the shot.

This morning I did some tests comparing the results of “M mode and AE-L” versus Av only mode, with camera set to Av one focuses wide open and then stop down the lens and immediately take the shot, I then change the f stop and shoot again, all the pictures are correctly exposed regardless of the f stop. In fact the exposure was better than using the “M AE-L” procedure.

This goes contrary to every thing I have read about using NON A type lenses.

Where am I going wrong :<)

Regards
Greg

Mike Cash · 07-07-2008, 03:53 PM

Originally Posted by Lowell Goudge

Mike

For non A lenses, I use manual mode, set the aperture and press the green button (you would use the AE-L button, this should stop the lens down and set metering.

Av mode as others have stated only shoots wide open.

Alternatively if you want to use the light meter, use DOF preview, and adjust manually, this has an advantage that you can deliberately over / under expose

Yes, that's correct in the case of K-mount lenses. M42 lenses are different because the camera has no way of stopping down the aperture. With them I find no point to stopping down the lens and then mashing a button when leaving the camera in Av will automatically set the shutter for me when I set the aperture. Deliberate over/under exposure can be achieved with the EV adjustment button.

Groundloop · 07-07-2008, 04:28 PM

Mike, I just noticed (don't know when you changed it), but I had to say...

Best. Signature. Ever.

Mike Cash · 07-08-2008, 07:52 AM

Originally Posted by Groundloop

Mike, I just noticed (don't know when you changed it), but I had to say...

Best. Signature. Ever.

A couple of days ago. I suppose it is mean-spirited, but that's one of the things that exasperates me.

pentagor · 07-08-2008, 02:11 PM

Originally Posted by pschlute

With the M lenses you can use Av mode BUT all you pictures will be taken at the lens maximum aperture, regardless of what you have set the aperture ring to.

Unfortunately this is not quite correct. The correct statement would be:
With the M lenses you can use Av mode, but all the metering will be done at the lens maximum aperture, regardless of what you have set the aperture ring to.

Pictures will be taken at aperture set with aperture ring, but the metering will be wrong (meaning underexposed images, if aperture is not wide open).

richard64 · 07-09-2008, 09:53 AM

Originally Posted by pentagor

Unfortunately this is not quite correct. The correct statement would be:
With the M lenses you can use Av mode, but all the metering will be done at the lens maximum aperture, regardless of what you have set the aperture ring to.

Pictures will be taken at aperture set with aperture ring, but the metering will be wrong (meaning underexposed images, if aperture is not wide open).

All I can say is that this is not the way my K100D works.

In Av mode I have just used a M35/2.8, I set the lens wide open and then took a series of photographs with the aperture ring set to 2.8, 5.6, 8, 11, 16, 22. According to your statement, only the first photo should have been exposed correctly. However, I found that all were correctly exposed. The EXIF shows that they were all taken at the same shutter speed, and by ear, I could tell no difference either. Finally, the DOF was exactly the same with all photos. Further, if I use the optical DOF preview I do not see any dimming in the VF. If I use M mode I do see dimming.

I am sure you will agree with me that from the evidence above my K100D is shooting all of the shots wide open in Av mode, regardless of the aperture ring.

Richard

Jodokast96 · 07-09-2008, 10:24 AM

As does mine.

pschlute · 07-09-2008, 05:44 PM

Originally Posted by pentagor

Unfortunately this is not quite correct. The correct statement would be:
With the M lenses you can use Av mode, but all the metering will be done at the lens maximum aperture, regardless of what you have set the aperture ring to.

Pictures will be taken at aperture set with aperture ring, but the metering will be wrong (meaning underexposed images, if aperture is not wide open).

Sorry Pentagor but it is you who are incorrect.

As has been pointed out, in Av mode the lens (M and "K") will not stop down.