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04-06-2011, 09:53 AM   #1
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Autofocus and Focusing screen

Guys, I don't want to start another complain thread on it (there are a few already). Rather, I want to share my experience after fw1.03. I sort of agree with many others (Smeggypants) claiming that the fw1.03 is somehow inconsistent in low light conditions: sometimes it works and sometimes not. I have the feeling (though nothing scientific here) that my previous body (k20d) in the same conditions would probably refuse focusing. In other words, perhaps the autofocus issue is there just because the new safox is much more sensitive in low light, and thus more prone to errors.

Nevertheless, I recently bought a split image, microprism collar focusing screen (I won't tell the brand, I'm not related anyhow with it!), and I can say that it helps getting rid of that 10-20% of missed low-light focuses, especially thanks to the clever Pentax quick-shift manual focus.

As a proof, I attach here a shot I took some days ago: as you can imagine, it was a steal, quick shot, no too much time for adjusting parameters. Low light, mainly tungsten light, focus on guy's face and recompose, with the face shifted within the microprism collar. I quickly noticed the wrong focus and adjusted it manually. The result is pretty good, in terms of focus. And taking shots is even more fun!

In conclusion, I actually feel this focussing screen such a great addition to the camera, that I wonder why Pentax is not installing it by default on every camera, especially in the semi-pro level like the k-5. I think that this is one of the things "I REALLY want" from future Pentax cameras.

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04-07-2011, 12:12 PM   #2
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QuoteOriginally posted by Paolo.Bosetti Quote
In conclusion, I actually feel this focussing screen such a great addition to the camera, that I wonder why Pentax is not installing it by default on every camera, especially in the semi-pro level like the k-5. I think that this is one of the things "I REALLY want" from future Pentax cameras.
Couldn't agree moore! Anyone listening there in Tokyo?

Kjell
04-07-2011, 12:26 PM   #3
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Lots of reasons not to have a split prism:
-increased cost
-dimmer viewfinder
-obscured central region
-admits failure of AF
-spot metering issues

Of course there are good reasons to have one too...
04-07-2011, 12:30 PM   #4
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Given how many of us buy screens with split prisms you'd think they would at least accommodate with a factory one we could buy

04-07-2011, 12:43 PM   #5
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The fact that the focusing screen is easily interchangeable is a good enough concession. Why burden everyone with a more expensive focusing screen they may not want/need? Give them a choice instead. That's a fine solution in my opinion.

QuoteOriginally posted by eddie1960 Quote
Given how many of us buy screens with split prisms you'd think they would at least accommodate with a factory one we could buy
Why? So you can pay more for it than you would any of the currently-available 3rd party options?
04-07-2011, 12:58 PM   #6
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The Pentax screens are cheaper than katzeyes for the ones they do sell, the other third party stuff is almost universally cut down older screens not current production. They are good (i have one) but if there had been a Pentax option at the same price as the other current pentax screens (around $80 AFAIK) well that's what i paid for a cut down nikon screen with gridlines so why wouldn't i buy the original
it would take nothing to add them into the production line (which is almost guaranteed to be a robotics line) just need to write the program for the treatment.
04-07-2011, 03:16 PM   #7
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QuoteOriginally posted by eddie1960 Quote
The Pentax screens are cheaper than katzeyes for the ones they do sell, the other third party stuff is almost universally cut down older screens not current production. They are good (i have one) but if there had been a Pentax option at the same price as the other current pentax screens (around $80 AFAIK) well that's what i paid for a cut down nikon screen with gridlines so why wouldn't i buy the original
it would take nothing to add them into the production line (which is almost guaranteed to be a robotics line) just need to write the program for the treatment.
The focusing screens at focusingscreen.com are about that price ($80 or so, some less, some more). Then you have the ridiculously priced Katz Eye option, which is... err... ridiculously priced.

Also, K3 and F6 focusing screens are still in production, not sure where you got the impression they weren't. Nikon still produces parts for the FM3A and F6 cameras, even if those cameras are no longer manufactured. (edit: wait, aren't F6 cameras still in production?) There's certainly nothing wrong with the fact that they're cut-down versions of full-size focusing screens. I don't get the point of spending 2x-3x as much for a Katz Eye version which is based on the K3 design anyways.

Sure, it would be nice if Pentax offered some of their own to supplement their current selection of AF focusing screens. But it's not like there's a gaping hole in the market, or a lack of choice.

Last edited by Hound Tooth; 04-07-2011 at 03:22 PM.
04-07-2011, 11:02 PM   #8
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En votoisi aina nikon "täyttä kakkaa"

04-08-2011, 05:48 AM   #9
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QuoteOriginally posted by sewebster Quote
Lots of reasons not to have a split prism:
-increased cost
-dimmer viewfinder
-obscured central region
-admits failure of AF
-spot metering issues
Hi
I have the Katz OptiBright and besides increased cost all of your other observations are incorrect.

Greetings
04-08-2011, 06:05 AM   #10
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"-dimmer viewfinder"
dimmer viewfinder depends on a number of things, for sure the prism darkens with slow lenses or stopped down manual m42, but in general my k5 screen is as bright if not brighter with the lenses i use (most of which are 2.8 or faster). and plus one on bright screen technology I don't use it (and metering complaints i've seen frequently are associated with this) but it is actually brighter than the original screen.

"-obscured central region"
obscured center region?? when it's not in focus maybe but that's the point otherwise it's just the same as gridlines which i also have (and are damn useful for composing quickly)

"-spot metering issues"
I've not had Spot metering issues, but admittedly some have complained of it. Mostly if i am spot metering i'm using my handheld and film, and the meter is usually with me. I need to do some tests i think

"-increased cost"
Agree there is an increased cost if it's a separate piece, but at the manufacturing end i'm pretty certain screens are robotics, the increased cost would be the time involved in programming the prism/split etching. otherwise no difference in cost than any of the other screens they do sell

"-admits failure of AF"
Huh?, it admits they have been marketing the ability to use great old lenses and this is the tool that would allow you t do that best. It also admits not all users will use the camera the same way and some may prefer fine focusing with manual focus

The real reason they should offer it is the same as the reason they offer the other screen. It's a revenue stream that costs little to implement and on a cost basis is likely a bigger ROI percentage wise than bodies. like the other screens just make them available, they will pick up sales currently lost to focusingscreen.com and katzeye (jinfinance will likely not lose sales as they are the cheap alternative)
Obviously a market exists or there wouldn't be 3 people competing in it
04-08-2011, 06:10 AM   #11
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QuoteOriginally posted by Hound Tooth Quote
The focusing screens at focusingscreen.com are about that price ($80 or so, some less, some more). Then you have the ridiculously priced Katz Eye option, which is... err... ridiculously priced.

Also, K3 and F6 focusing screens are still in production, not sure where you got the impression they weren't. Nikon still produces parts for the FM3A and F6 cameras, even if those cameras are no longer manufactured. (edit: wait, aren't F6 cameras still in production?) There's certainly nothing wrong with the fact that they're cut-down versions of full-size focusing screens. I don't get the point of spending 2x-3x as much for a Katz Eye version which is based on the K3 design anyways.

Sure, it would be nice if Pentax offered some of their own to supplement their current selection of AF focusing screens. But it's not like there's a gaping hole in the market, or a lack of choice.
Not sure how long the F6 option will last. F6 was made at the plant closed due to the earthquake in Sendai. Moving and retooling a plant for FF digital makes sense. Retooling for the F6 likely makes no sense I don't think they did many runs on it and would not be surprised if this is the end of the line for it. But is this screen the same screen the ff digital uses? then it will survive
Jinfinance cuts down older screens
Focusing screen.com cheap options i think are older screens as well, but they do use the Nikon (and some Canon screens) I have a Nikon variant myself.
Thought about an Optibright one from katzeye, and given my aging eyes next screen may well be that, the brighter screen can offset my dimming aging eyes, like my +3 diopeter offsets my eyes ability to focus
04-08-2011, 07:25 AM   #12
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I can only speak for the Katz screen, but spot metering (which I use a lot) has never been a problem for me. There is an approx. 1/3 f-stop consideration but since this is a constant shift one can adjust for it for each lens. Its no big deal. But anyway, I look at what I want to shoot and use an estimated EV compensation amount I think is required before even taking the first shot. Maybe age and experience is a benefit here. Because of this the Katz screen discrepancy has no relevance.

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04-08-2011, 08:57 AM   #13
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QuoteOriginally posted by sewebster Quote
Lots of reasons not to have a split prism:
-increased cost
-dimmer viewfinder
-obscured central region
-admits failure of AF
-spot metering issues
Since someone else already came out with brands: the screen I mentioned is actually a Katzeye with optibright treatment. Of the reasons you mention I am sure that in my case there is absolutely no issue with spot metering nor dimmer view finder (conversely, I rather find it brighter). It is also resistant to central region black out up to ƒ4.5 and –believe it or not– it is still usable up to ƒ22. Anyway, since I only have Limiteds and DA* lenses, never had a problem with central region obscuration.

It is true, it increases the cost: but we are talking about the top Pentax camera, not an entry level. I personally would have been happy in paying $100 more for it. Katzeye screens are costly, but I bet that when mass produced as standard camera part they would not alter too significantly the selling price.

Finally: now that all this talking about k5 AF issues has gone on for months, I agree that there is some kind of psychological effect (it would sound like "ok, we admit that our AF sucks, so please revert to manual when you need it"). But if Pentax (as other brands) would have not drop the split image screen during the Analog/Digital transition, this would have not been the case.

They have such a great thing that is the quickshift focus, but it is only 50% useful without a good focusing screen!
04-08-2011, 01:23 PM   #14
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I would probably actually be FOR a split prism screen either by default or as an option, was just listing some possible issues.

For the "dimmer viewfinder" point, I meant for a plain ground glass screen. My understanding is that the current plastic screens area designed to increase light transmission at the expense of improper depth of field display for fast lenses. My understanding is that the optibright treatment has the same problem, as per the katzeye website where they recommend the non-optibright if you use mostly very fast lenses.

I don't see how you can really argue against the obscured central region... even without blackout, any time the center is out of focus you will see the microprisms or split prism etc. I can completely accept this as being non-annoying to some people however. I'm just saying that SOME people might not want it. It might be nice to have new screens available with smaller prisms designed for today's smaller sensors.

Paolo got my point about AF. It's basically politics. If Pentax puts in a split prism then some might interpret that as saying "just in case our AF malfunctions." Of course I think this is dumb, because being able to more easily use tons of MF lenses would be fantastic. Pentax might rather you buy new lenses though

Perhaps I should have left the spot metering off. I don't know enough about that problem or lack thereof. Sorry.
04-08-2011, 01:46 PM   #15
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I can see the prism annoying some people, that's why i'd be happy to see it as an option, designed for aps c instead of cut down so the prism is centered properly and if the gridlines are present so they are as well. not to knock the aftermarket guys but this is an issue with cutting down ff screens
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