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Wordslinger · 01-09-2011, 04:37 AM

Hey folks,

I've just purchased a couple of (old) prime lenses. One is a 28mm f2.5 (Tamron w/adaptall) and the other is a 50mm f2 Pentax (Asahi) lens. I've also purchased a couple of zoom lenses (one is a Tamron 80-210 and the other is a Vivitar 100-300). These are all manual focus lenses.

Here's my issue/question:

When using the zoom lenses, I can hold the shutter half way and it will beep to acknowledge the focus. It's quite accurate when using the zoom lenses.

However, when I attach the prime's, that focus 'beep' confirmation is off. I have to fiddle back and forth, back and forth. And the focus indicator never stays lit. Just a blip. And when it does beep, it's actually not quite in focus... I have to focus completely by eye with these primes.

Any idea what's going on here?

edit:
I may have just had an idea which I will test shortly. Being that the depth of field is so shallow when you get down to f2 or so, could it be that the camera's autofocus is having trouble locking on?

Paleo Pete · 01-09-2011, 12:10 PM

I've seen that for a long time, I usually don't pay much attention to the beep, other than using it to let me know if I'm close. I mainly pay attention to what I see in the viewfinder, that's what matters...

I don't know if the beep is accurate for manual focus lenses or not, with the kind of wildlife shots I try to get even a tiny bit off shows, and I get bad focus no matter what I do quite often, especially with fast moving subjects like birds.

I'd say don't pay a lot of attention to the beep, pay attention to what you see.

Oh and remember the three P's...Practice, Practice, Practice.

Wordslinger · 01-09-2011, 01:28 PM

I've been thinking of looking for a magnifying eyepiece for my Kx. I often find it difficult looking through the viewfinder to really get a sense for where the perfect focus is, especially if the subject is at a bit of a distance. With a zoom, I can zoom in, focus, zoom out and recompose. Have you tried any magnifying eye pieces for your viewfinder? I would always focus manually if I could see a bit better.

I miss the viewfinders of old 35mm cameras, the half circle type that are in focus when the image lines up.

MSM · 01-09-2011, 01:52 PM

Originally posted by Wordslinger

I've been thinking of looking for a magnifying eyepiece for my Kx. I often find it difficult looking through the viewfinder to really get a sense for where the perfect focus is, especially if the subject is at a bit of a distance. With a zoom, I can zoom in, focus, zoom out and recompose. Have you tried any magnifying eye pieces for your viewfinder? I would always focus manually if I could see a bit better.

I miss the viewfinders of old 35mm cameras, the half circle type that are in focus when the image lines up.

I would look into a split prism. I know that the Kx is not supposed to have a changeable vf, but many here have done that. There are several threads here regarding the various makers and the way to change the vf screen. I used to have one for my k10. I found it to be more helpful than the magnifying eyecup.

Wordslinger · 01-09-2011, 02:09 PM

Hey, fantastic! I had no idea you could get replacement focusing screens. I'm already finding a number of options.

Ira · 01-09-2011, 02:25 PM

Try this before you buy anything:

Focus with your lenses wide open, then stop down.

Older lenses, even fast ones, don't play nice with AF.

Also, your primes are trickier to lock in focus because the focus rings on them are more precise than the zooms. Tiny movements throw it off focus as far as the confirmation goes, but that doesn't necessarily make the shot out of focus.

**boriscleto** · 01-09-2011, 02:53 PM

Originally posted by Ira

Try this before you buy anything:

Focus with your lenses wide open, then stop down.

Older lenses, even fast ones, don't play nice with AF.

He's not using screw-mounts, he's using K-mounts. K-mounts are always wide open until you hit the green button.

AF cameras are notorious for being tricky to focus with MF lenses faster than f/2.8 because of the lack of micro-prism focusing aids in the focusing screen.

repaap · 01-11-2011, 06:50 AM

I think that you will have to learn focusing by eye. I have faced that problem too. But with my K-7. micro adjustment for lense might be good too...it might be off. But I don't know if it is possible in K-X.

I have been thinking of purchasing a splitprism too...but after practising I have managed to get focus at place. Also what i have read from other threads from this forum, about focus praceting is not a bad idea. It does not cost you anything at digital era, just effort

Ira · 01-11-2011, 08:16 AM

Originally posted by boriscleto

He's not using screw-mounts, he's using K-mounts. K-mounts are always wide open until you hit the green button.

AF cameras are notorious for being tricky to focus with MF lenses faster than f/2.8 because of the lack of micro-prism focusing aids in the focusing screen.

How does the Green button stop down the lens on an Asahi Takumar?

orly_andico · 01-11-2011, 08:41 AM

I'll second the split-screen. I've had one in my K20D for years, and I just received another one (from jinfinance again on ebay) for my Canon 40D.

The K20D required some adjustment of the shim to get MF and AF to agree, but the 40D (as confirmed with my single EF lens, and my manual-focusing with Live View) is accurate, no need to shim.

The split-image screen just takes all the guesswork out of manual focusing (assuming it's bright enough for the split-circle to not go dark). It's just annoying when it doesn't agree with AF!

**boriscleto** · 01-11-2011, 01:43 PM

Originally posted by Ira

How does the Green button stop down the lens on an Asahi Takumar?

Where did he say anything about an Asahi Takumar? He mentions a Tamron Adaptall and an Asahi Pentax 50 f/2, both K-mount. That is unless Asahi produced a 50mm f/2 Tak that I've never heard of.

ryan s · 01-11-2011, 02:01 PM

Some say the focus confirm is more accurate when you focus past your intended point, then slowly come backwards. In my experience, it does work a little better.

Still, the best focus confirm tool is your eye

Does the K-x offer interchangeable screens? I was under the understanding it doesn't but I'd love to be proved wrong on that point.

**boriscleto** · 01-11-2011, 02:18 PM

Originally posted by ryan s

Does the K-x offer interchangeable screens? I was under the understanding it doesn't but I'd love to be proved wrong on that point.

Officially no. But they can be bought on the internet (Katzeye, Focusingscreen.com, etc.) and installed.

ryan s · 01-11-2011, 02:21 PM

Aha, nice! Maybe it's the older ones which didn't allow the user to change them (K100D, etc) without disassembling the camera...or maybe I just can't remember anything clearly

Using a darker *ist screen in mine helped the manual focusing immensely.

**felixkh** · 01-11-2011, 04:17 PM

Originally posted by MSM

I would look into a split prism. I know that the Kx is not supposed to have a changeable vf, but many here have done that. There are several threads here regarding the various makers and the way to change the vf screen. I used to have one for my k10. I found it to be more helpful than the magnifying eyecup.

The focusing screen of the K-x can be changed as I have done it before. I got mine from Focusing Screen. I bought the K3 version as it is bright enough

01-09-2011, 04:37 AM	#1
Wordslinger New Member Join Date: Dec 2010 Location: Ontario Posts: 20	Prime Lenses on a KX Hey folks, I've just purchased a couple of (old) prime lenses. One is a 28mm f2.5 (Tamron w/adaptall) and the other is a 50mm f2 Pentax (Asahi) lens. I've also purchased a couple of zoom lenses (one is a Tamron 80-210 and the other is a Vivitar 100-300). These are all manual focus lenses. Here's my issue/question: When using the zoom lenses, I can hold the shutter half way and it will beep to acknowledge the focus. It's quite accurate when using the zoom lenses. However, when I attach the prime's, that focus 'beep' confirmation is off. I have to fiddle back and forth, back and forth. And the focus indicator never stays lit. Just a blip. And when it does beep, it's actually not quite in focus... I have to focus completely by eye with these primes. Any idea what's going on here? edit: I may have just had an idea which I will test shortly. Being that the depth of field is so shallow when you get down to f2 or so, could it be that the camera's autofocus is having trouble locking on?

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01-09-2011, 12:10 PM	#2
Paleo Pete Veteran Member Join Date: Jun 2010 Location: Texas Photos: Gallery \| Albums Posts: 2,880	I've seen that for a long time, I usually don't pay much attention to the beep, other than using it to let me know if I'm close. I mainly pay attention to what I see in the viewfinder, that's what matters... I don't know if the beep is accurate for manual focus lenses or not, with the kind of wildlife shots I try to get even a tiny bit off shows, and I get bad focus no matter what I do quite often, especially with fast moving subjects like birds. I'd say don't pay a lot of attention to the beep, pay attention to what you see. Oh and remember the three P's...Practice, Practice, Practice.

01-09-2011, 01:28 PM	#3
Wordslinger New Member Join Date: Dec 2010 Location: Ontario Posts: 20 Original Poster	I've been thinking of looking for a magnifying eyepiece for my Kx. I often find it difficult looking through the viewfinder to really get a sense for where the perfect focus is, especially if the subject is at a bit of a distance. With a zoom, I can zoom in, focus, zoom out and recompose. Have you tried any magnifying eye pieces for your viewfinder? I would always focus manually if I could see a bit better. I miss the viewfinders of old 35mm cameras, the half circle type that are in focus when the image lines up.

01-09-2011, 01:52 PM	#4
MSM Veteran Member Join Date: Dec 2007 Location: Alabama Photos: Gallery Posts: 994	Originally posted by Wordslinger I've been thinking of looking for a magnifying eyepiece for my Kx. I often find it difficult looking through the viewfinder to really get a sense for where the perfect focus is, especially if the subject is at a bit of a distance. With a zoom, I can zoom in, focus, zoom out and recompose. Have you tried any magnifying eye pieces for your viewfinder? I would always focus manually if I could see a bit better. I miss the viewfinders of old 35mm cameras, the half circle type that are in focus when the image lines up. I would look into a split prism. I know that the Kx is not supposed to have a changeable vf, but many here have done that. There are several threads here regarding the various makers and the way to change the vf screen. I used to have one for my k10. I found it to be more helpful than the magnifying eyecup.

01-09-2011, 02:09 PM	#5
Wordslinger New Member Join Date: Dec 2010 Location: Ontario Posts: 20 Original Poster	Hey, fantastic! I had no idea you could get replacement focusing screens. I'm already finding a number of options.

01-09-2011, 02:25 PM	#6
Ira Inactive Account Join Date: Mar 2009 Location: Coral Springs, FL Photos: Gallery \| Albums Posts: 5,216	Try this before you buy anything: Focus with your lenses wide open, then stop down. Older lenses, even fast ones, don't play nice with AF. Also, your primes are trickier to lock in focus because the focus rings on them are more precise than the zooms. Tiny movements throw it off focus as far as the confirmation goes, but that doesn't necessarily make the shot out of focus.

01-09-2011, 02:53 PM	#7
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,477	Originally posted by Ira Try this before you buy anything: Focus with your lenses wide open, then stop down. Older lenses, even fast ones, don't play nice with AF. He's not using screw-mounts, he's using K-mounts. K-mounts are always wide open until you hit the green button. AF cameras are notorious for being tricky to focus with MF lenses faster than f/2.8 because of the lack of micro-prism focusing aids in the focusing screen.

01-11-2011, 06:50 AM	#8
repaap Pentaxian Join Date: Oct 2010 Photos: Gallery \| Albums Posts: 6,242	I think that you will have to learn focusing by eye. I have faced that problem too. But with my K-7. micro adjustment for lense might be good too...it might be off. But I don't know if it is possible in K-X. I have been thinking of purchasing a splitprism too...but after practising I have managed to get focus at place. Also what i have read from other threads from this forum, about focus praceting is not a bad idea. It does not cost you anything at digital era, just effort

01-11-2011, 08:16 AM	#9
Ira Inactive Account Join Date: Mar 2009 Location: Coral Springs, FL Photos: Gallery \| Albums Posts: 5,216	Originally posted by boriscleto He's not using screw-mounts, he's using K-mounts. K-mounts are always wide open until you hit the green button. AF cameras are notorious for being tricky to focus with MF lenses faster than f/2.8 because of the lack of micro-prism focusing aids in the focusing screen. How does the Green button stop down the lens on an Asahi Takumar?

01-11-2011, 08:41 AM	#10
orly_andico Forum Member Join Date: Feb 2009 Location: Manila, Philippines Posts: 97	I'll second the split-screen. I've had one in my K20D for years, and I just received another one (from jinfinance again on ebay) for my Canon 40D. The K20D required some adjustment of the shim to get MF and AF to agree, but the 40D (as confirmed with my single EF lens, and my manual-focusing with Live View) is accurate, no need to shim. The split-image screen just takes all the guesswork out of manual focusing (assuming it's bright enough for the split-circle to not go dark). It's just annoying when it doesn't agree with AF!

01-11-2011, 01:43 PM	#11
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,477	Originally posted by Ira How does the Green button stop down the lens on an Asahi Takumar? Where did he say anything about an Asahi Takumar? He mentions a Tamron Adaptall and an Asahi Pentax 50 f/2, both K-mount. That is unless Asahi produced a 50mm f/2 Tak that I've never heard of.

01-11-2011, 02:01 PM	#12
ryan s Veteran Member Join Date: Jan 2008 Location: Madison, WI Photos: Gallery Posts: 2,383	Some say the focus confirm is more accurate when you focus past your intended point, then slowly come backwards. In my experience, it does work a little better. Still, the best focus confirm tool is your eye Does the K-x offer interchangeable screens? I was under the understanding it doesn't but I'd love to be proved wrong on that point.

01-11-2011, 02:18 PM	#13
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,477	Originally posted by ryan s Does the K-x offer interchangeable screens? I was under the understanding it doesn't but I'd love to be proved wrong on that point. Officially no. But they can be bought on the internet (Katzeye, Focusingscreen.com, etc.) and installed.

01-11-2011, 02:21 PM	#14
ryan s Veteran Member Join Date: Jan 2008 Location: Madison, WI Photos: Gallery Posts: 2,383	Aha, nice! Maybe it's the older ones which didn't allow the user to change them (K100D, etc) without disassembling the camera...or maybe I just can't remember anything clearly Using a darker *ist screen in mine helped the manual focusing immensely.

01-11-2011, 04:17 PM	#15
felixkh Site Supporter Join Date: Nov 2008 Location: Singapore Photos: Gallery Posts: 1,201	Originally posted by MSM I would look into a split prism. I know that the Kx is not supposed to have a changeable vf, but many here have done that. There are several threads here regarding the various makers and the way to change the vf screen. I used to have one for my k10. I found it to be more helpful than the magnifying eyecup. The focusing screen of the K-x can be changed as I have done it before. I got mine from Focusing Screen. I bought the K3 version as it is bright enough

Prime Lenses on a KX

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