This is a MASSIVE revalation for me. Aperture with M lenses

Isaac314 · 09-12-2008, 10:07 AM

I have been using my 50mm 1.4 as well as a couple others happily but with the knowledge that i have one huge limitation; i can only use these lenses with the aperture wide open, unless i decouple the lens from the body and hold it on.

Today i had the lens on and i was testing out the lens using flash and various apertures, i pressed the green button and the aperture closed. Firstly i didnt know the green button did that, and secondly the camera just controlled my lens' aperture, the only difference? i am on M mode. I tried optical preview and fired off a shot, and its there, the lens aperture does what it did on my old film body. I realise the camera can't read the aperture and do stopped down metering, but the fact that i can use my lens on anything but 1.4 is new to me. On any mode other than M the aperture stays open no matter what i put it on (i usually use Av).

I feel so stupid! Did everyone else already get this? I think its the fact that i rarely use manual.

Damn!

séamuis · 09-12-2008, 10:16 AM

yea its pretty common knowledge that non 'A' lenses have to use stop down metering ie: the 'green' or 'AE-lock' button (for us K100D users). you should probably read the manual

. that or come here and read through the Pentax photography knowledge base. https://www.pentaxforums.com/forums/pentax-photography-knowledge-base/32-can-...ist-ds-dl.html

pentaxist · 09-12-2008, 10:17 AM

This was a revelation for me too ... since I have Firmware 2.00 on my ist DS

Isaac314 · 09-12-2008, 11:43 AM

Oh, so the green button is closing the aperture, checking it and setting the correct speed. That is clever and this sounds like a very efficient way of working.

I already was pretty much fine with using my manual lens but stuck on 1.4 because i've been using it on Av all the time... I swear i was looking inside the camera, i could see the little lever, i was shouting at it "WHY DONT YOU PUT SOME EFFORT IN AND CLOSE MY APERTURE FOR ME"

Mike.P® · 09-12-2008, 12:33 PM

Although I have found on my K10D that the lower the aperture you use the more it overexposes and therefore you have to compensate.

Gooshin · 09-12-2008, 01:17 PM

yeah this is standard knowledge... its in the manual.

mel · 09-12-2008, 01:20 PM

Pardon my ignorance now but why not just use the aperture ring to change the aperture? When I'm in AV mode with an M lens, and I change the aperture with the ring, the camera does just fine adjusting the shutter speed to compensate for the smaller opening. Am I missing something?

Stratman · 09-12-2008, 01:25 PM

Mel, in AV mode, the lens stays wide open, regardless of the aperture ring setting. ( M lenses only, A lenses work just like the newer lenses, IF you have the Ap ring set to the A position )

mel · 09-12-2008, 01:41 PM

Originally posted by Stratman

Mel, in AV mode, the lens stays wide open, regardless of the aperture ring setting. ( M lenses only, A lenses work just like the newer lenses, IF you have the Ap ring set to the A position )

Oh I see my problem. I was using the screw-mount lenses to look at that issue. It's just the k-mounts that they don't move. I have a few screwmount manual lenses. The aperture ring works just like "old-school" on those. Green-button away!

lithos · 09-12-2008, 02:23 PM

Aye. You wouldn't know it from reading most of the mainstream literature, because no one who rights the mainstream literature has probably never shot a Pentax in his/her life, let alone shot an M lens on a "crippled" KAF2 body. Most reviews of a Pentax camera will simply say, "All Pentax digital SLR bodies are compatible with older Pentax film lenses (FA, F and A mounts) as well as newer lenses (DA and DA* mounts)" (that excerpt from Photo.net's outline of the Pentax DSLRs.)

It is, sadly, getting to be a bit of a secret. And if anyone comes along and tells you that Nikon cameras have the best backwards-compatibility with older lenses, since the F mount has been around since 1959, you have my permissions to hit them on the head with a K1000.

PollitowuzHere · 09-12-2008, 04:37 PM

You could also hold down the DoF preview lever (it has to be in mechanical DoF preview) and it will give you a live meter.

09-12-2008, 10:07 AM	#1
Isaac314 Veteran Member Join Date: Aug 2008 Location: London Photos: Gallery Posts: 417	This is a MASSIVE revalation for me. Aperture with M lenses I have been using my 50mm 1.4 as well as a couple others happily but with the knowledge that i have one huge limitation; i can only use these lenses with the aperture wide open, unless i decouple the lens from the body and hold it on. Today i had the lens on and i was testing out the lens using flash and various apertures, i pressed the green button and the aperture closed. Firstly i didnt know the green button did that, and secondly the camera just controlled my lens' aperture, the only difference? i am on M mode. I tried optical preview and fired off a shot, and its there, the lens aperture does what it did on my old film body. I realise the camera can't read the aperture and do stopped down metering, but the fact that i can use my lens on anything but 1.4 is new to me. On any mode other than M the aperture stays open no matter what i put it on (i usually use Av). I feel so stupid! Did everyone else already get this? I think its the fact that i rarely use manual. Damn!

09-12-2008, 10:16 AM	#2
séamuis Banned Join Date: Oct 2007 Location: Savannah, U.S./Baguio City, P.H. Posts: 5,979	yea its pretty common knowledge that non 'A' lenses have to use stop down metering ie: the 'green' or 'AE-lock' button (for us K100D users). you should probably read the manual. that or come here and read through the Pentax photography knowledge base. https://www.pentaxforums.com/forums/pentax-photography-knowledge-base/32-can-...ist-ds-dl.html

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Aperture, Old Lenses and werewolves	marlon	Pentax SLR Lens Discussion	2	10-10-2008 11:47 AM
Revalation with the DA*	offertonhatter	Pentax SLR Lens Discussion	3	08-01-2008 03:16 PM
How do A lenses report aperture?	ftpaddict	Pentax SLR Lens Discussion	3	05-15-2008 09:00 AM
Aperture ring on FA lenses	ankit	Pentax DSLR Discussion	8	02-04-2008 04:54 AM
A great revalation.	jbrowning	Pentax DSLR Discussion	3	10-21-2007 09:13 AM

09-12-2008, 10:17 AM	#3
pentaxist New Member Join Date: Sep 2008 Location: Belgium Posts: 1	This was a revelation for me too ... since I have Firmware 2.00 on my ist DS

09-12-2008, 11:43 AM	#4
Isaac314 Veteran Member Join Date: Aug 2008 Location: London Photos: Gallery Posts: 417 Original Poster	Oh, so the green button is closing the aperture, checking it and setting the correct speed. That is clever and this sounds like a very efficient way of working. I already was pretty much fine with using my manual lens but stuck on 1.4 because i've been using it on Av all the time... I swear i was looking inside the camera, i could see the little lever, i was shouting at it "WHY DONT YOU PUT SOME EFFORT IN AND CLOSE MY APERTURE FOR ME"

09-12-2008, 12:33 PM	#5
Mike.P® Veteran Member Join Date: Mar 2008 Location: New Milton, Hampshire, UK Photos: Gallery \| Albums Posts: 2,154	Although I have found on my K10D that the lower the aperture you use the more it overexposes and therefore you have to compensate.

09-12-2008, 01:17 PM	#6
Gooshin Veteran Member Join Date: Sep 2007 Location: Toronto, the one in Canada. Posts: 5,610	yeah this is standard knowledge... its in the manual.

09-12-2008, 01:20 PM	#7
mel Veteran Member Join Date: Feb 2008 Location: Virginia Photos: Gallery \| Albums Posts: 2,531	Pardon my ignorance now but why not just use the aperture ring to change the aperture? When I'm in AV mode with an M lens, and I change the aperture with the ring, the camera does just fine adjusting the shutter speed to compensate for the smaller opening. Am I missing something?

09-12-2008, 01:25 PM	#8
Stratman Veteran Member Join Date: Mar 2007 Location: St Louis, Missouri U S A Photos: Gallery \| Albums Posts: 2,464	Mel, in AV mode, the lens stays wide open, regardless of the aperture ring setting. ( M lenses only, A lenses work just like the newer lenses, IF you have the Ap ring set to the A position )

09-12-2008, 01:41 PM	#9
mel Veteran Member Join Date: Feb 2008 Location: Virginia Photos: Gallery \| Albums Posts: 2,531	Originally posted by Stratman Mel, in AV mode, the lens stays wide open, regardless of the aperture ring setting. ( M lenses only, A lenses work just like the newer lenses, IF you have the Ap ring set to the A position ) Oh I see my problem. I was using the screw-mount lenses to look at that issue. It's just the k-mounts that they don't move. I have a few screwmount manual lenses. The aperture ring works just like "old-school" on those. Green-button away!

09-12-2008, 02:23 PM	#10
lithos Inactive Account Join Date: Oct 2007 Location: Brisbane, QLD, AUS Posts: 3,261	Aye. You wouldn't know it from reading most of the mainstream literature, because no one who rights the mainstream literature has probably never shot a Pentax in his/her life, let alone shot an M lens on a "crippled" KAF2 body. Most reviews of a Pentax camera will simply say, "All Pentax digital SLR bodies are compatible with older Pentax film lenses (FA, F and A mounts) as well as newer lenses (DA and DA* mounts)" (that excerpt from Photo.net's outline of the Pentax DSLRs.) It is, sadly, getting to be a bit of a secret. And if anyone comes along and tells you that Nikon cameras have the best backwards-compatibility with older lenses, since the F mount has been around since 1959, you have my permissions to hit them on the head with a K1000.

09-12-2008, 04:37 PM	#11
PollitowuzHere Senior Member Join Date: May 2008 Location: Puerto Rico Posts: 110	You could also hold down the DoF preview lever (it has to be in mechanical DoF preview) and it will give you a live meter.