Are there lenses that are "green button resistant"?

i5_david · 03-10-2016, 12:48 PM

Hey friends,

I know of and use the green button method to meter my manual lenses on K5 II (latest firmware). I got today two from ebay. One porst 35-105 and a Exakta 80-200.
I put on the Porst first and went in the city to test the lens. Choosing aperture and optical preview (turning the shutter button), metering with green button. works flawless.

Back home I tried the Exakta and all of a sudden the green button is not working. Put on 50 1.7 green button does his job. Porst?Still working.
Exakta, nothing. Are there Lenses that are some kind of not working with green button metering, or is the lens broken?

I am glad for any help! Thanks in advanced! Let me know if you need more infos or I missed anything.

pathdoc · 03-10-2016, 12:59 PM

Look at the metal of the lens where it contacts the mount face. Does it contact the mount face or does it stand off a short dsitance? If it does contact the mount face, is it bare metal (shiny silver) or anodised (black/same colour as the rest of the lens exterior)?

If it is anodised, there is a failure to short out one of the pins that permits green button metering and stop down. I have struck this issue with my K-5 with an inherited 28mm Vivitar lens. The cure is electricians' conductive tape applied to the back of the lens where it presses against the data pins in the mount.

If it doesn't contact the mount, you might still be able to put some conductive tape across the pins.

Can you post a picture of the rear of the Exakta lens?

johnyates · 03-10-2016, 12:59 PM

The back of the lens needs to be unpainted metal in order to short the data pins in the camera mount for the green button to work.

**marcusBMG** · 03-10-2016, 12:59 PM

This may be pertinent

https://www.pentaxforums.com/forums/116-pentax-k-r/271872-tests-plated-vs-pai...r-whats-t.html

npc · 03-10-2016, 12:59 PM - **1 Like**

Define "not working" ... is this Exakta a m42 lens to begin with?

i5_david · 03-10-2016, 01:25 PM

thank you guys!
I made a quick capture with my phone (find it attached). It is a K-Mount no 42.
And I would say it is not painted, isnt it?!

I had before that one only primes that are Manual. I just noticed a little noise appearing when I am shaking the lens in my hand.
Dont know if this is normal but maybe the lens got a damage during transport!?

The aperture, the focus, the locallength sounds and feels right, though, hmm

stevebrot · 03-10-2016, 01:28 PM

Originally posted by johnyates

The back of the lens needs to be unpainted metal in order to short the data pins in the camera mount for the green button to work.

...at least with recent model Pentax bodies. The pin that must have contact is the data pin on the body. See diagram (courtesy of Bojidar Dimitrov's K-mount Page):

Steve

i5_david · 03-10-2016, 01:31 PM

Originally posted by npc

Define "not working"

sorry missed your one... not working as doing nothing with the aperture.
Pushing the green button is actually metering the light and changing in different light situations but its always metering open wide (f4.5) but not adjusting the blades.

OH, forgot: if I attach it to my K1000 the apperture is sending some information to the metering system and if I change the aperture it has influence to the light meter at the side

stevebrot · 03-10-2016, 01:31 PM

Originally posted by i5_david

thank you guys!
I made a quick capture with my phone (find it attached). It is a K-Mount no 42.
And I would say it is not painted, isnt it?!

I had before that one only primes that are Manual. I just noticed a little noise appearing when I am shaking the lens in my hand.
Dont know if this is normal but maybe the lens got a damage during transport!?

The aperture, the focus, the locallength sounds and feels right, though, hmm

Hmmmm...the base is definitely bare metal. Does the aperture ring work in that it opens and closes the iris with the lens off the camera? When stopped down, does the actuator lever reliably open/close the iris with no binding or hesitation at all click stops? The action should be "snappy".

Steve

pathdoc · 03-10-2016, 01:33 PM

The next thing to check is that the Exakta's aperture is actually working. Set it halfway between full open and full closed, then flick the aperture stop down lever (the one nearest the protective flange). If nothing moves, or it appears to stay wide open, or moves sluggishly, the problem is in the lens.

I've had this happen with a couple of lenses; turns out their aperture blades were oily and jammed open. An easy service job for a competent technician.

i5_david · 03-10-2016, 01:39 PM

Nope, the lens seems ok regarding the aperture. If I use it the way you describe it it works just as it should. I can adjust the f Number with the ring and it feels snappy and I can open and reclose the aperture with the little metal pin thing.

stevebrot · 03-10-2016, 02:32 PM

Originally posted by i5_david

Nope, the lens seems ok regarding the aperture. If I use it the way you describe it it works just as it should. I can adjust the f Number with the ring and it feels snappy and I can open and reclose the aperture with the little metal pin thing.

Well, that is stranger still.

One last thing...are you sure the lens is fully mounted on the camera? I noticed that it has a very prominent actuator guard similar to certain Vivitar models. With those lenses the ears on the bayonet will engage, but the lens will not fully rotate on. The focus index on the lens should be at the top at 12 o'clock when properly mounted.

Steve

**UncleVanya** · 03-10-2016, 02:58 PM

Originally posted by i5_david

sorry missed your one... not working as doing nothing with the aperture.
Pushing the green button is actually metering the light and changing in different light situations but its always metering open wide (f4.5) but not adjusting the blades.

OH, forgot: if I attach it to my K1000 the apperture is sending some information to the metering system and if I change the aperture it has influence to the light meter at the side

That's not exactly what's going on with DSLR's. The K1000 or older non-crippled mounts use an aperture sensing lever to know the position of the aperture ring. DSLR's don't use this. The green button is NOT wide open metering. It stops down to whatever f/stop you have selected (it has no idea what this is - it just pushes the lever and meters).

Not a Number · 03-10-2016, 09:39 PM

Is the auto aperture lever bent? If it is not engaging the corresponding actuator in the camera than it's not going to work properly.

Set the aperture on the ring to the highest f-stop (f22-32). Mount the lens and with the camera off look through the front of the lens. Is it wide open (normal operation) or closed down (something is wrong)?

It's normal for many lenses to have something make noise when you shake them. It depends on the lens.

i5_david · 03-12-2016, 03:15 AM

Originally posted by Not a Number

Mount the lens and with the camera off look through the front of the lens. Is it wide open (normal operation) or closed down (something is wrong)?

If I have the Lens in my hand and turn to f22 the aperture is closed. In the moment I put it back on the camera the aperture will open up wide as you describe "normal operation"

Originally posted by stevebrot

are you sure the lens is fully mounted on the camera?

Hello Steve, I double checked this and I am quite sure I mounted it correctly.

Originally posted by UncleVanya

The green button is NOT wide open metering.

I know that. What I meant is that the metering is working on the K1000, so that there should be at some point any adjustment that delivers information to the kamera (e.g. the lever is moving and working and the lens seems to be ok on the film camera ).

You guys have serious insight! Thanks for your help! Deeply appreciate it. Do you have any other ideas what this could be?
I attached to other shots of that lens. one is showing the 12 o'clock when mounted.

03-10-2016, 12:48 PM	#1
i5_david Veteran Member Join Date: Feb 2016 Posts: 332	Are there lenses that are "green button resistant"? Hey friends, I know of and use the green button method to meter my manual lenses on K5 II (latest firmware). I got today two from ebay. One porst 35-105 and a Exakta 80-200. I put on the Porst first and went in the city to test the lens. Choosing aperture and optical preview (turning the shutter button), metering with green button. works flawless. Back home I tried the Exakta and all of a sudden the green button is not working. Put on 50 1.7 green button does his job. Porst?Still working. Exakta, nothing. Are there Lenses that are some kind of not working with green button metering, or is the lens broken? I am glad for any help! Thanks in advanced! Let me know if you need more infos or I missed anything.

03-10-2016, 01:25 PM	#6
i5_david Veteran Member Join Date: Feb 2016 Posts: 332 Original Poster	thank you guys! I made a quick capture with my phone (find it attached). It is a K-Mount no 42. And I would say it is not painted, isnt it?! I had before that one only primes that are Manual. I just noticed a little noise appearing when I am shaking the lens in my hand. Dont know if this is normal but maybe the lens got a damage during transport!? The aperture, the focus, the locallength sounds and feels right, though, hmm Last edited by i5_david; 05-02-2016 at 12:13 PM.

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03-10-2016, 12:59 PM	#2
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	Look at the metal of the lens where it contacts the mount face. Does it contact the mount face or does it stand off a short dsitance? If it does contact the mount face, is it bare metal (shiny silver) or anodised (black/same colour as the rest of the lens exterior)? If it is anodised, there is a failure to short out one of the pins that permits green button metering and stop down. I have struck this issue with my K-5 with an inherited 28mm Vivitar lens. The cure is electricians' conductive tape applied to the back of the lens where it presses against the data pins in the mount. If it doesn't contact the mount, you might still be able to put some conductive tape across the pins. Can you post a picture of the rear of the Exakta lens?

03-10-2016, 12:59 PM	#3
johnyates Pentaxian Join Date: Aug 2011 Location: Saskatoon, SK Photos: Albums Posts: 1,345	The back of the lens needs to be unpainted metal in order to short the data pins in the camera mount for the green button to work.

03-10-2016, 12:59 PM	#4
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	This may be pertinent https://www.pentaxforums.com/forums/116-pentax-k-r/271872-tests-plated-vs-pai...r-whats-t.html

03-10-2016, 12:59 PM - 1 Like	#5
npc Veteran Member Join Date: Apr 2013 Posts: 313	Define "not working" ... is this Exakta a m42 lens to begin with?

03-10-2016, 01:28 PM	#7
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by johnyates The back of the lens needs to be unpainted metal in order to short the data pins in the camera mount for the green button to work. ...at least with recent model Pentax bodies. The pin that must have contact is the data pin on the body. See diagram (courtesy of Bojidar Dimitrov's K-mount Page): Steve

03-10-2016, 01:31 PM	#8
i5_david Veteran Member Join Date: Feb 2016 Posts: 332 Original Poster	Originally posted by npc Define "not working" sorry missed your one... not working as doing nothing with the aperture. Pushing the green button is actually metering the light and changing in different light situations but its always metering open wide (f4.5) but not adjusting the blades. OH, forgot: if I attach it to my K1000 the apperture is sending some information to the metering system and if I change the aperture it has influence to the light meter at the side

03-10-2016, 01:31 PM	#9
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by i5_david thank you guys! I made a quick capture with my phone (find it attached). It is a K-Mount no 42. And I would say it is not painted, isnt it?! I had before that one only primes that are Manual. I just noticed a little noise appearing when I am shaking the lens in my hand. Dont know if this is normal but maybe the lens got a damage during transport!? The aperture, the focus, the locallength sounds and feels right, though, hmm Hmmmm...the base is definitely bare metal. Does the aperture ring work in that it opens and closes the iris with the lens off the camera? When stopped down, does the actuator lever reliably open/close the iris with no binding or hesitation at all click stops? The action should be "snappy". Steve

03-10-2016, 01:33 PM	#10
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	The next thing to check is that the Exakta's aperture is actually working. Set it halfway between full open and full closed, then flick the aperture stop down lever (the one nearest the protective flange). If nothing moves, or it appears to stay wide open, or moves sluggishly, the problem is in the lens. I've had this happen with a couple of lenses; turns out their aperture blades were oily and jammed open. An easy service job for a competent technician.

03-10-2016, 01:39 PM	#11
i5_david Veteran Member Join Date: Feb 2016 Posts: 332 Original Poster	Nope, the lens seems ok regarding the aperture. If I use it the way you describe it it works just as it should. I can adjust the f Number with the ring and it feels snappy and I can open and reclose the aperture with the little metal pin thing.

03-10-2016, 02:32 PM	#12
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by i5_david Nope, the lens seems ok regarding the aperture. If I use it the way you describe it it works just as it should. I can adjust the f Number with the ring and it feels snappy and I can open and reclose the aperture with the little metal pin thing. Well, that is stranger still. One last thing...are you sure the lens is fully mounted on the camera? I noticed that it has a very prominent actuator guard similar to certain Vivitar models. With those lenses the ears on the bayonet will engage, but the lens will not fully rotate on. The focus index on the lens should be at the top at 12 o'clock when properly mounted. Steve

03-10-2016, 02:58 PM	#13
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,460	Originally posted by i5_david sorry missed your one... not working as doing nothing with the aperture. Pushing the green button is actually metering the light and changing in different light situations but its always metering open wide (f4.5) but not adjusting the blades. OH, forgot: if I attach it to my K1000 the apperture is sending some information to the metering system and if I change the aperture it has influence to the light meter at the side That's not exactly what's going on with DSLR's. The K1000 or older non-crippled mounts use an aperture sensing lever to know the position of the aperture ring. DSLR's don't use this. The green button is NOT wide open metering. It stops down to whatever f/stop you have selected (it has no idea what this is - it just pushes the lever and meters).

03-10-2016, 09:39 PM	#14
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Is the auto aperture lever bent? If it is not engaging the corresponding actuator in the camera than it's not going to work properly. Set the aperture on the ring to the highest f-stop (f22-32). Mount the lens and with the camera off look through the front of the lens. Is it wide open (normal operation) or closed down (something is wrong)? It's normal for many lenses to have something make noise when you shake them. It depends on the lens.