K20D related terms - pls. explain

bartbrn · 07-05-2009, 08:30 AM

There are a couple (well, more than a couple...) terms I don't understand, and I hope someone can explain them to me, or point me in the direction of finding out for myself.

1. What is a "crippled KAF2" mount?
2. What is "front/back focus correction"?
3. What is "diopter adjustment"?

Thanks for your help!

Bart Brown

AlexL · 08-13-2009, 09:34 AM

Originally posted by bartbrn

There are a couple (well, more than a couple...) terms I don't understand, and I hope someone can explain them to me, or point me in the direction of finding out for myself.

1. What is a "crippled KAF2" mount?
2. What is "front/back focus correction"?
3. What is "diopter adjustment"?

Thanks for your help!

Bart Brown

1. The mount refers to metal ring on the SLR camera body where the lens mounts to. Over the years, the mounts evolve to allow for new lens features, and as such the mounts have been given different names (Pentax's various K, KAF, KAF2, etc.) The "crippled" part refers to a mechanical feature that's no longer included in these mounts. This feature allows the camera to know what the aperture is on a manual M-series lens, so the crippled-KAF2 mount is missing this feature. This missing feature is not a big deal since you can still meter with these old lenses anyway with the green button. More info on the different Pentax mounts here:
Pentax K mount - Wikipedia, the free encyclopedia

2. Front focusing is when a lens tends to focusing in front of the subject (closer to the camera) than it is suppose to, while back focus is when alens focuses behind the subject (further away from the camera) than it's suppose to. It's not unusual to find a lens that has a small amount of front or back focusing, but it's usually so small that no one really notices in most situations. The K20D has a feature that lets you counteract the effects of front and back focusing so that the lens will focus more accurately.

3. If diopter adjustment doesn't sound familiar to you, then you probably don't wear glasses. It is a setting in the optical viewfinder that lets people who normally wear glasses see clearly through the viewfinder without their glasses. It is a small slider above the viewfinder. I recently borrowed a friend's K10D, and he wears glasses so when I looked through the viewfinder everything was blurry to me (I don't wear glasses). I adjusted the diopter slider and it was perfect for me again (I adjusted it back when I returned the camera).

I hope that helps.

AlexL

07-05-2009, 08:30 AM	#1
bartbrn New Member Join Date: Jul 2009 Location: Clinton, CT Posts: 10	K20D related terms - pls. explain There are a couple (well, more than a couple...) terms I don't understand, and I hope someone can explain them to me, or point me in the direction of finding out for myself. 1. What is a "crippled KAF2" mount? 2. What is "front/back focus correction"? 3. What is "diopter adjustment"? Thanks for your help! Bart Brown

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08-13-2009, 09:34 AM	#2
AlexL Senior Member Join Date: Aug 2007 Location: Athens, GA Posts: 137	Originally posted by bartbrn There are a couple (well, more than a couple...) terms I don't understand, and I hope someone can explain them to me, or point me in the direction of finding out for myself. 1. What is a "crippled KAF2" mount? 2. What is "front/back focus correction"? 3. What is "diopter adjustment"? Thanks for your help! Bart Brown 1. The mount refers to metal ring on the SLR camera body where the lens mounts to. Over the years, the mounts evolve to allow for new lens features, and as such the mounts have been given different names (Pentax's various K, KAF, KAF2, etc.) The "crippled" part refers to a mechanical feature that's no longer included in these mounts. This feature allows the camera to know what the aperture is on a manual M-series lens, so the crippled-KAF2 mount is missing this feature. This missing feature is not a big deal since you can still meter with these old lenses anyway with the green button. More info on the different Pentax mounts here: Pentax K mount - Wikipedia, the free encyclopedia 2. Front focusing is when a lens tends to focusing in front of the subject (closer to the camera) than it is suppose to, while back focus is when alens focuses behind the subject (further away from the camera) than it's suppose to. It's not unusual to find a lens that has a small amount of front or back focusing, but it's usually so small that no one really notices in most situations. The K20D has a feature that lets you counteract the effects of front and back focusing so that the lens will focus more accurately. 3. If diopter adjustment doesn't sound familiar to you, then you probably don't wear glasses. It is a setting in the optical viewfinder that lets people who normally wear glasses see clearly through the viewfinder without their glasses. It is a small slider above the viewfinder. I recently borrowed a friend's K10D, and he wears glasses so when I looked through the viewfinder everything was blurry to me (I don't wear glasses). I adjusted the diopter slider and it was perfect for me again (I adjusted it back when I returned the camera). I hope that helps. AlexL