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06-26-2010, 03:19 AM   #16
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So. Is there any shims to buy?

I dont know if i want to install a split screen, because i like the screen i the K-7, i often use the boxes and lines alot for composing.

06-26-2010, 03:43 AM   #17
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my humble appologies for making a thread in panic

I have now taken some time here at this forum and found the "Shims" and "Katz" threads, and have also now learned that this issue is a factory thingy. The screens are callibrated to work with AF lenses and it works fine!

But putting a fast lens as the 50 1,2 will make most of us realise that the focusing screen is "off". It also seems that its very visible wih the FA 50 1,4.

So the question is whether one wants to use a Split Screen or just shimming the stock screen!

I have read somewhere that splitscreens doesnt go well with exposure using AF lenses and flash. Please correct me regarding this.

I think i rather try to shim the stock screen for my A 50. And still have the stock screen for flash and AF use.

I will mail Pentax in Sweden, if they have the shims for K-7

Are these for the K-7?
https://www.pentaxforums.com/forums/pentax-dslr-discussion/88289-k7-screen-shims.html#post954277
06-26-2010, 07:05 AM   #18
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Using a third-party focusing screen with a central split image rangefinder or microprism will not affect matrix and center weighted metering but will definitely give funky exposure readings in spot metering as these focusing aids are right smack where the spot meter reading is taken from. Used the Nikon K3 and Canon EC-L focusing screens that were cut down to size for the K-7 and have not had any problems with exposure using AF lenses.
06-26-2010, 04:40 PM   #19
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Using a split screen can affect metering. But using one doesn't mean it necessarily will. I used one for quite a while, and metering (matrix, center, and spot) were all fine. But for some reason, flash was a mess, to the tune of 4+ stops of under-exposure. It just took me a while to notice because I don't use flash all that much. But as I said, using one is not a guarantee of issues. Many use them and things work just fine.

06-26-2010, 07:17 PM   #20
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To the OP...don't shim your screen. There is likely nothing wrong with its position.

Almost everyone on this forum who shoots with f/2 and faster manual focus lenses has your issue, regardless of camera body. The problem lies with the viewfinder and screen design. This issue has come up many times in the past on this forum and the short answer is this:
  • Regardless of lens maximum aperture, the DOF in the viewfinder is the same at f/4 as at f/1.2. This is a factor of the screen design. The small size of the viewfinder image also exaggerates the DOF.
  • Precision manual focus with faster lenses is not possible with the Pentax screen as a result
  • The camera's AF system (focus confirm) is no more reliable. There is a reason why there are very few fast AF lenses. They show up the weak points of the system.
  • The solution is to purchase an aftermarket screen with a focus aid
I was having a terrible time using my manual focus lenses, particularly my Jupiter-9 85/2. It has very limited depth of field wide open. The problem disappeared when I replaced the stock screen with a Katz Eye. It was expensive, but worth it. Other forum members have had good luck with screens from eBay and from focusingscreen.com (LINK).


Steve
06-26-2010, 08:16 PM   #21
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QuoteQuote:
stevebrot: To the OP...don't shim your screen. There is likely nothing wrong with its position.

Almost everyone on this forum who shoots with f/2 and faster manual focus lenses has your issue, regardless of camera body. The problem lies with the viewfinder and screen design. This issue has come up many times in the past on this forum and the short answer is this:

* Regardless of lens maximum aperture, the DOF in the viewfinder is the same at f/4 as at f/1.2. This is a factor of the screen design. The small size of the viewfinder image also exaggerates the DOF.
* Precision manual focus with faster lenses is not possible with the Pentax screen as a result
* The camera's AF system (focus confirm) is no more reliable. There is a reason why there are very few fast AF lenses. They show up the weak points of the system.
* The solution is to purchase an aftermarket screen with a focus aid

I was having a terrible time using my manual focus lenses, particularly my Jupiter-9 85/2. It has very limited depth of field wide open. The problem disappeared when I replaced the stock screen with a Katz Eye. It was expensive, but worth it. Other forum members have had good luck with screens from eBay and from focusingscreen.com (LINK).


Steve
Mr OP, the above post by Steve is all you need--it is SPOT ON! : )
06-27-2010, 12:29 AM   #22
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QuoteOriginally posted by stevebrot Quote
To the OP...don't shim your screen. There is likely nothing wrong with its position.

Almost everyone on this forum who shoots with f/2 and faster manual focus lenses has your issue, regardless of camera body. The problem lies with the viewfinder and screen design. This issue has come up many times in the past on this forum and the short answer is this:
  • Regardless of lens maximum aperture, the DOF in the viewfinder is the same at f/4 as at f/1.2. This is a factor of the screen design. The small size of the viewfinder image also exaggerates the DOF.
  • Precision manual focus with faster lenses is not possible with the Pentax screen as a result
  • The camera's AF system (focus confirm) is no more reliable. There is a reason why there are very few fast AF lenses. They show up the weak points of the system.
  • The solution is to purchase an aftermarket screen with a focus aid
I was having a terrible time using my manual focus lenses, particularly my Jupiter-9 85/2. It has very limited depth of field wide open. The problem disappeared when I replaced the stock screen with a Katz Eye. It was expensive, but worth it. Other forum members have had good luck with screens from eBay and from focusingscreen.com (LINK).


Steve
Thanks alot for the nice answers!

I have a few more questions. I see in some of the threads about focusing screens that meetering will be affected. Can that be a negative effect when using AF lenses.

I have also seen metioned by some that flash is behaving different. This worries me a litle as i use flash very much.

I do have to consider if its worth putting a splitscreen in the camera, because i use AF lenses and flash more than i use manual lenses.

So...im not really sure what to do
06-27-2010, 01:35 AM   #23
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Changing the focus screen takes 2-5 minutes. For what they do, it's more than worth it to try it out and see how it affects your camera. If it doesn't work, you can always sell it at little to no loss and try a different one. The one I used was one of the cheap ones. It could have been defective, it could be my camera, who knows. Maybe a different cheap one would work. Maybe I need a higher end Katz Eye. Maybe none will work for me. One day maybe I'll get off my lazy butt and find out, though I'm probably too cheap to ever spring for the Katz Eye.

06-27-2010, 10:07 AM   #24
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QuoteQuote:
the swede:Thanks alot for the nice answers!

I have a few more questions. I see in some of the threads about focusing screens that meetering will be affected. Can that be a negative effect when using AF lenses.

I have also seen metioned by some that flash is behaving different. This worries me a litle as i use flash very much.

I do have to consider if its worth putting a splitscreen in the camera, because i use AF lenses and flash more than i use manual lenses.

So...im not really sure what to do
Focus screens do not affect AF. Split prisms are known for affecting Spot Metering in particular. The Katz Eye people post a warning concerning the use of their screen and Spot Metering at their site.

Only you can decide if you need a split prism. Split Prisms are a boon to those of us who have fast, older galss and want to enjoy it. That said, Split Prisms in no way slow me down from using my newer, AF glass, nor flash for that matter.

Like everything else in life, choices come with consequences (costs)--only you can weigh the various costs vs benefits and decide accordingly for your situation.

So gather all the facts and make the best choice you can--good luck.

Last edited by Jewelltrail; 06-27-2010 at 10:33 AM. Reason: correction
06-27-2010, 10:20 AM   #25
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QuoteOriginally posted by Jewelltrail Quote
Focus screens do not affect AF. Split prisms are known for affecting Spot Metering in particular. The Katz Eye people post a warning concerning the use of their screen and Spot Metering at their site.

Only you can decide if you need a split prism. Split Prisms are a boon to those of us who have fast, older galss and want to enjoy it. That said, Split Prisms in no way slow me down from using my newer, AF glass, nor flash for that matter.

Like everything else in life, choices come with consequences (costs)--only you can way the various costs vs benefits and decide accordingly for your situation.

So gather all the facts and make the best choice you can--good luck.
Thanks! I've come to that point know Deciding what to do.
06-28-2010, 07:42 PM   #26
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Swede I to like the K-7 focusing screen. I shoot 95% of the time manually. I don't have an A50 f1.2 lens though so I can not comment on it. I do have an A50 f1.4 which I love for portraits. I never shoot wide open either especially for portraits as the DOF is just to shallow I shoot around f2.8-3.2 to insure a decent amount of the face in focus without missing. I find the k-7 screen to work really well to see focus.

I have a Katz Eye for my K20D. It was an improvement over the stock screen working very well. But when I got the K-7 I felt Pentax really got the focusing screen right that I didn't need a Katz Eye. I haven't even entertained the thought of getting one for the K-7.

Earlier I mentioned the diopter. I don't think I was clear with my thoughts on it. I was suggesting maybe you could correct the focus by adjusting the diopter for when you have the A50 f1.2 on the camera. Does that make any sense? It would seem like a simple solution compared to shims or a new focusing screen.
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