Infinity Adjustment

**BruceBanner** · 03-25-2018, 08:43 PM

What's the deal with infinity adjustments... like... how can you tell if you suspect the lens you own may benefit from it?

I own a SMC Pentax-A 24mm 2.8, I enjoy a lot of the shots it produces but sometimes I feel that when I push it to focus infinity there is still a softness there that shouldn't be, like it needs to go a tad farther. It could be me of course (user error), but I did note that a 'For Sale' post recently for a partially broken A 24mm 2.8 (missing piece to make it work in 'A' mode) also had an infinity adjustment made during it's attempted repair. It got me thinking... maybe mines needs it to?

a) how to test?

b) how to adjust?

Cheers!

Bruce

Adam · 03-25-2018, 08:53 PM

Originally posted by BruceBanner

What's the deal with infinity adjustments... like... how can you tell if you suspect the lens you own may benefit from it?

I own a SMC Pentax-A 24mm 2.8, I enjoy a lot of the shots it produces but sometimes I feel that when I push it to focus infinity there is still a softness there that shouldn't be, like it needs to go a tad farther. It could be me of course (user error), but I did note that a 'For Sale' post recently for a partially broken A 24mm 2.8 (missing piece to make it work in 'A' mode) also had an infinity adjustment made during it's attempted repair. It got me thinking... maybe mines needs it to?

a) how to test?

b) how to adjust?

Cheers!

Bruce

If you suspect a lens isn't able to focus to infinity, test it out in live view, and stop it down to rule out softness wide open. It should be able to render distant objects. Adjustment could be done at a repair shop, I think. Also keep in mind that the amount that the focusing ring can go past infinity may vary with ambient temperature.

Ronald Oakes · 03-25-2018, 09:57 PM

That was my lens listed for sale.
I cant really describe just "how" I determined it wasn't quite hitting infinity , other than it just wasn't quite there . I always felt that it was hitting the hard stop just shy as my images weren't quite as sharp as I knew the lens could be.
After Eric adjusted it , the difference was easy to see. I asked him to intentionally set it a hair past the oo stop, as there is nothing worse than to come up short.
I shoot a lot in Live View with focus peaking , and would rather have it a hair past oo to come back to focus , rather than not quite getting there in the first place.
This is a somewhat common occurrence on older MF lenses I'm finding out.

**BruceBanner** · 03-25-2018, 10:06 PM

Originally posted by Ronald Oakes

That was my lens listed for sale.
I cant really describe just "how" I determined it wasn't quite hitting infinity , other than it just wasn't quite there . I always felt that it was hitting the hard stop just shy as my images weren't quite as sharp as I knew the lens could be.
After Eric adjusted it , the difference was easy to see. I asked him to intentionally set it a hair past the oo stop, as there is nothing worse than to come up short.
This is a somewhat common occurrence on older MF lenses I'm finding out.

That's kinda what I'm feeling at the moment, but I don't like to trust my instincts too much. I took a picture of my daughter on the weekend (it just hit Explore now), and it's a very close up shot with that lens, the sharpness is incredible (on the K-1), her eyes just perfectly in focus, so I feel that sharpness is somehow missing from infinity landscape stuff I tend to do more with that lens.

pinholecam · 03-25-2018, 10:09 PM

Originally posted by BruceBanner

I feel that when I push it to focus infinity there is still a softness there that shouldn't be

Thats about the best that I can go with unfortunately if you have only one camera.
I usually base it on what I recall from my usage on another camera and also with my A7 which has the adapters which all allow the focus to go past infinity.

**BruceBanner** · 03-25-2018, 10:19 PM

Originally posted by pinholecam

Thats about the best that I can go with unfortunately if you have only one camera.
I usually base it on what I recall from my usage on another camera and also with my A7 which has the adapters which all allow the focus to go past infinity.

Oh I have a Pentax KP as well as K-1, can we ascertain more data from having two camera bodies?

Ronald Oakes · 03-25-2018, 10:21 PM

While in LV with Focus Peaking....I noticed it would get right at the point for FP to "pop" into view......but never quite made it.
I have lots of manual lenses so knew what was going on.
When a inexpensive little Rikenon P 28mm 2.8 was sharper than the SMC-A 24mm at infinity , I started investigating. My suspicions were easily confirmed.
Eric also verified it was coming up short.

---------- Post added 03-25-18 at 22:23 ----------

Originally posted by BruceBanner

Oh I have a Pentax KP as well as K-1, can we ascertain more data from having two camera bodies?

Unless your camera is somehow defective in the registration distance or mount department , this isn't a camera issue , its a Lens issue.

**BruceBanner** · 03-25-2018, 10:28 PM

Originally posted by Ronald Oakes

While in LV with Focus Peaking....I noticed it would get right at the point for FP to "pop" into view......but never quite made it.
I have lots of manual lenses so knew what was going on.
When a inexpensive little Rikenon P 28mm 2.8 was sharper than the SMC-A 24mm at infinity , I started investigating. My suspicions were easily confirmed.
Eric also verified it was coming up short.

---------- Post added 03-25-18 at 22:23 ----------

Unless your camera is somehow defective in the registration distance or mount department , this isn't a camera issue , its a Lens issue.

Maybe it's worth posting off to Pentax Australia for an inspection (I forget the people that handle that stuff for Australia, they're really good IIRC). I really like the lens.

Ronald Oakes · 03-25-2018, 10:48 PM

Originally posted by BruceBanner

Maybe it's worth posting off to Pentax Australia for an inspection (I forget the people that handle that stuff for Australia, they're really good IIRC). I really like the lens.

Try this first. Put your camera in LV with focus peaking......then focus out to about 40-50 feet.....slowly focus to infinity and watch your screen. If you don't see the focus peaking "Pop'' or brighten up right as you are hitting the infinity stop then there is a problem.
Were talking splitting hairs here with the focus ring , and watching closely the pattern in LV with FP.
When I test a lens , I love it when the hard stop engages right after the FP "Pop" effect......that means I'm not going to come up short and will have the utmost sharpness out of whatever lens I'm testing.

I should have also added to open your lens up to 2.8 first ! Also try it at different Apertures to see where you get the maximum effect in LV with FP.

Sorry.....I'm not doing a very good job of trying to explain this

Unregistered User 8 · 03-26-2018, 03:10 AM - **1 Like**

Originally posted by BruceBanner

Maybe it's worth posting off to Pentax Australia for an inspection (I forget the people that handle that stuff for Australia, they're really good IIRC). I really like the lens.

C.R.Kennedy

LensBeginner · 03-26-2018, 05:49 AM

That also happens with my M 200/4.
I tried to open it but don't have JIS screwdrivers of the required size.
Noticed it with the K-01, hadn't noticed it with the K100Ds, so it really was something minor.

pinholecam · 03-26-2018, 06:32 AM

Originally posted by BruceBanner

Oh I have a Pentax KP as well as K-1, can we ascertain more data from having two camera bodies?

My M85/2 which I had for years and ok for infinity focus from K7, K5, K30 was somehow way out on the K1.
My K24/2.8 needed a bit of adjustment and after that, I feel that it works rather fine as a landscape 24mm for FF.
I have infinity focus issues on 2 other lenses as well on the K1.
So I sent all of them for adjustment.

So yes, to me using another camera can serve as a guide if the lens is out.

The local service center told me that the camera was in spec.
Personally, I have encountered matching issues between cameras (fine on another K5, issues on my K5, etc)
I am not surprised since the camera and lens have tolerances and the stack up tolerances may be fine between new lens > new camera, but not with old ones.

Kombivan · 03-26-2018, 07:01 AM

I have a 28-200mm sigma bought it new works perfectly on a film camera but on digital it seems short in infinity and its out of focus all through the range on any dslr I have any thoughts?

**Just1MoreDave** · 03-26-2018, 07:55 AM - **1 Like**

Originally posted by LensBeginner

That also happens with my M 200/4.
I tried to open it but don't have JIS screwdrivers of the required size.
Noticed it with the K-01, hadn't noticed it with the K100Ds, so it really was something minor.

This is either pedantic or useful information, but you don't need screwdrivers to open that lens. The barrel in front of the focus ring unscrews, similar to the K135/2.5. But then you need screwdrivers for the actual adjustment, so it's kind of pedantic, sorry.

The moon or stars are good for testing infinity focus if you have dark enough skies. A comparison to another lens of the same focal length should work. If you have to look closely to pick a winner at 100 feet but one is obviously fuzzy at infinity, that's a problem.

LensBeginner · 03-26-2018, 08:58 AM

Originally posted by Just1MoreDave

This is either pedantic or useful information, but you don't need screwdrivers to open that lens. The barrel in front of the focus ring unscrews, similar to the K135/2.5. But then you need screwdrivers for the actual adjustment, so it's kind of pedantic, sorry.

The moon or stars are good for testing infinity focus if you have dark enough skies. A comparison to another lens of the same focal length should work. If you have to look closely to pick a winner at 100 feet but one is obviously fuzzy at infinity, that's a problem.

Thanks! was following the pics on wiratama, but it was some months ago

03-25-2018, 08:43 PM	#1
BruceBanner Site Supporter Join Date: Dec 2015 Posts: 5,404	Infinity Adjustment What's the deal with infinity adjustments... like... how can you tell if you suspect the lens you own may benefit from it? I own a SMC Pentax-A 24mm 2.8, I enjoy a lot of the shots it produces but sometimes I feel that when I push it to focus infinity there is still a softness there that shouldn't be, like it needs to go a tad farther. It could be me of course (user error), but I did note that a 'For Sale' post recently for a partially broken A 24mm 2.8 (missing piece to make it work in 'A' mode) also had an infinity adjustment made during it's attempted repair. It got me thinking... maybe mines needs it to? a) how to test? b) how to adjust? Cheers! Bruce

03-25-2018, 08:53 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by BruceBanner What's the deal with infinity adjustments... like... how can you tell if you suspect the lens you own may benefit from it? I own a SMC Pentax-A 24mm 2.8, I enjoy a lot of the shots it produces but sometimes I feel that when I push it to focus infinity there is still a softness there that shouldn't be, like it needs to go a tad farther. It could be me of course (user error), but I did note that a 'For Sale' post recently for a partially broken A 24mm 2.8 (missing piece to make it work in 'A' mode) also had an infinity adjustment made during it's attempted repair. It got me thinking... maybe mines needs it to? a) how to test? b) how to adjust? Cheers! Bruce If you suspect a lens isn't able to focus to infinity, test it out in live view, and stop it down to rule out softness wide open. It should be able to render distant objects. Adjustment could be done at a repair shop, I think. Also keep in mind that the amount that the focusing ring can go past infinity may vary with ambient temperature. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

03-25-2018, 10:48 PM	#9
Ronald Oakes Pentaxian Join Date: Jul 2017 Location: Virginia Posts: 1,583	Originally posted by BruceBanner Maybe it's worth posting off to Pentax Australia for an inspection (I forget the people that handle that stuff for Australia, they're really good IIRC). I really like the lens. Try this first. Put your camera in LV with focus peaking......then focus out to about 40-50 feet.....slowly focus to infinity and watch your screen. If you don't see the focus peaking "Pop'' or brighten up right as you are hitting the infinity stop then there is a problem. Were talking splitting hairs here with the focus ring , and watching closely the pattern in LV with FP. When I test a lens , I love it when the hard stop engages right after the FP "Pop" effect......that means I'm not going to come up short and will have the utmost sharpness out of whatever lens I'm testing. I should have also added to open your lens up to 2.8 first ! Also try it at different Apertures to see where you get the maximum effect in LV with FP. Sorry.....I'm not doing a very good job of trying to explain this Last edited by Ronald Oakes; 03-25-2018 at 11:24 PM.

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03-25-2018, 09:57 PM	#3
Ronald Oakes Pentaxian Join Date: Jul 2017 Location: Virginia Posts: 1,583	That was my lens listed for sale. I cant really describe just "how" I determined it wasn't quite hitting infinity , other than it just wasn't quite there . I always felt that it was hitting the hard stop just shy as my images weren't quite as sharp as I knew the lens could be. After Eric adjusted it , the difference was easy to see. I asked him to intentionally set it a hair past the oo stop, as there is nothing worse than to come up short. I shoot a lot in Live View with focus peaking , and would rather have it a hair past oo to come back to focus , rather than not quite getting there in the first place. This is a somewhat common occurrence on older MF lenses I'm finding out.

03-25-2018, 10:06 PM	#4
BruceBanner Site Supporter Join Date: Dec 2015 Posts: 5,404 Original Poster	Originally posted by Ronald Oakes That was my lens listed for sale. I cant really describe just "how" I determined it wasn't quite hitting infinity , other than it just wasn't quite there . I always felt that it was hitting the hard stop just shy as my images weren't quite as sharp as I knew the lens could be. After Eric adjusted it , the difference was easy to see. I asked him to intentionally set it a hair past the oo stop, as there is nothing worse than to come up short. This is a somewhat common occurrence on older MF lenses I'm finding out. That's kinda what I'm feeling at the moment, but I don't like to trust my instincts too much. I took a picture of my daughter on the weekend (it just hit Explore now), and it's a very close up shot with that lens, the sharpness is incredible (on the K-1), her eyes just perfectly in focus, so I feel that sharpness is somehow missing from infinity landscape stuff I tend to do more with that lens.

03-25-2018, 10:09 PM	#5
pinholecam Pentaxian Join Date: Oct 2009 Location: North Photos: Gallery Posts: 4,706	Originally posted by BruceBanner I feel that when I push it to focus infinity there is still a softness there that shouldn't be Thats about the best that I can go with unfortunately if you have only one camera. I usually base it on what I recall from my usage on another camera and also with my A7 which has the adapters which all allow the focus to go past infinity.

03-25-2018, 10:19 PM	#6
BruceBanner Site Supporter Join Date: Dec 2015 Posts: 5,404 Original Poster	Originally posted by pinholecam Thats about the best that I can go with unfortunately if you have only one camera. I usually base it on what I recall from my usage on another camera and also with my A7 which has the adapters which all allow the focus to go past infinity. Oh I have a Pentax KP as well as K-1, can we ascertain more data from having two camera bodies?

03-25-2018, 10:21 PM	#7
Ronald Oakes Pentaxian Join Date: Jul 2017 Location: Virginia Posts: 1,583	While in LV with Focus Peaking....I noticed it would get right at the point for FP to "pop" into view......but never quite made it. I have lots of manual lenses so knew what was going on. When a inexpensive little Rikenon P 28mm 2.8 was sharper than the SMC-A 24mm at infinity , I started investigating. My suspicions were easily confirmed. Eric also verified it was coming up short. ---------- Post added 03-25-18 at 22:23 ---------- Originally posted by BruceBanner Oh I have a Pentax KP as well as K-1, can we ascertain more data from having two camera bodies? Unless your camera is somehow defective in the registration distance or mount department , this isn't a camera issue , its a Lens issue.

03-25-2018, 10:28 PM	#8
BruceBanner Site Supporter Join Date: Dec 2015 Posts: 5,404 Original Poster	Originally posted by Ronald Oakes While in LV with Focus Peaking....I noticed it would get right at the point for FP to "pop" into view......but never quite made it. I have lots of manual lenses so knew what was going on. When a inexpensive little Rikenon P 28mm 2.8 was sharper than the SMC-A 24mm at infinity , I started investigating. My suspicions were easily confirmed. Eric also verified it was coming up short. ---------- Post added 03-25-18 at 22:23 ---------- Unless your camera is somehow defective in the registration distance or mount department , this isn't a camera issue , its a Lens issue. Maybe it's worth posting off to Pentax Australia for an inspection (I forget the people that handle that stuff for Australia, they're really good IIRC). I really like the lens.

03-26-2018, 03:10 AM - 1 Like	#10
Unregistered User 8 Closed Account Join Date: Mar 2015 Photos: Gallery Posts: 8,694	Originally posted by BruceBanner Maybe it's worth posting off to Pentax Australia for an inspection (I forget the people that handle that stuff for Australia, they're really good IIRC). I really like the lens. C.R.Kennedy

03-26-2018, 05:49 AM	#11
LensBeginner Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 4,696	That also happens with my M 200/4. I tried to open it but don't have JIS screwdrivers of the required size. Noticed it with the K-01, hadn't noticed it with the K100Ds, so it really was something minor.

03-26-2018, 06:32 AM	#12
pinholecam Pentaxian Join Date: Oct 2009 Location: North Photos: Gallery Posts: 4,706	Originally posted by BruceBanner Oh I have a Pentax KP as well as K-1, can we ascertain more data from having two camera bodies? My M85/2 which I had for years and ok for infinity focus from K7, K5, K30 was somehow way out on the K1. My K24/2.8 needed a bit of adjustment and after that, I feel that it works rather fine as a landscape 24mm for FF. I have infinity focus issues on 2 other lenses as well on the K1. So I sent all of them for adjustment. So yes, to me using another camera can serve as a guide if the lens is out. The local service center told me that the camera was in spec. Personally, I have encountered matching issues between cameras (fine on another K5, issues on my K5, etc) I am not surprised since the camera and lens have tolerances and the stack up tolerances may be fine between new lens > new camera, but not with old ones.

03-26-2018, 07:01 AM	#13
Kombivan Veteran Member Join Date: Nov 2017 Photos: Gallery Posts: 576	I have a 28-200mm sigma bought it new works perfectly on a film camera but on digital it seems short in infinity and its out of focus all through the range on any dslr I have any thoughts?

03-26-2018, 07:55 AM - 1 Like	#14
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	Originally posted by LensBeginner That also happens with my M 200/4. I tried to open it but don't have JIS screwdrivers of the required size. Noticed it with the K-01, hadn't noticed it with the K100Ds, so it really was something minor. This is either pedantic or useful information, but you don't need screwdrivers to open that lens. The barrel in front of the focus ring unscrews, similar to the K135/2.5. But then you need screwdrivers for the actual adjustment, so it's kind of pedantic, sorry. The moon or stars are good for testing infinity focus if you have dark enough skies. A comparison to another lens of the same focal length should work. If you have to look closely to pick a winner at 100 feet but one is obviously fuzzy at infinity, that's a problem.

03-26-2018, 08:58 AM	#15
LensBeginner Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 4,696	Originally posted by Just1MoreDave This is either pedantic or useful information, but you don't need screwdrivers to open that lens. The barrel in front of the focus ring unscrews, similar to the K135/2.5. But then you need screwdrivers for the actual adjustment, so it's kind of pedantic, sorry. The moon or stars are good for testing infinity focus if you have dark enough skies. A comparison to another lens of the same focal length should work. If you have to look closely to pick a winner at 100 feet but one is obviously fuzzy at infinity, that's a problem. Thanks! was following the pics on wiratama, but it was some months ago