Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-25-2007, 04:55 PM   #1
Veteran Member




Join Date: Feb 2007
Location: Ontario
Photos: Gallery
Posts: 630
Any conclusions re: K10D + Katz w/ Optibrite?

I'm sorry I know this has been posted before, and there is lots of information on DPreview, but I'm having a hard time deciphering it all having joined mid-stream.

Here's what I got from Rachael Katz a few days ago:

Q: Do you have any comments on light metering with the K10D and OptiBrite coating?

A: "Regarding the light metering in the K10D, we found that the only major issue
is when using spot metering mode with slower lenses. If you use spot
metering with a lens having a maximum aperture smaller than f2.0 (larger f
number), you will have overexposure problems. If you are using a lens
slower than f2.0, you can either use a different metering mode (CWA and
Evaluative work fine) or you can use spot metering and dial in negative
exposure compensation to achieve correct exposures."

I'll be shooting exclusively with m42 lenses, so accurate stop-down metering and viewfinder brightness are both important to me, and I'd rather not give up either if I have the choice. Sean C. also did a test for me that showed stop-down metering on the k10d to err slightly towards overexposure at smaller apertures (read f16).

I'm wondering if I should stick to the regular screen or take my chances with the coating...

02-26-2007, 01:46 PM   #2
Veteran Member
volosong's Avatar

Join Date: Sep 2006
Location: Antelope Valley, SoCal
Photos: Gallery
Posts: 663
Rachael used my K10D body for her engineering studies. In exchange, she gave me the option of accepting any product they made. I chose the split screen, microprism collar with the Pentax AF etched brackets, all topped off with the OptiBright treatment.

I've really gotten to like those AF brackets. They are most useful in keeping a horizon level. I've come to rely on them often. And, with manual focusing, I can't live without the split screen. Don't care much for the microprism collar. That's a 'take it or leave' it issue. Don't really care one way or the other.

And finally, to finish setting the background for my following comments. I have a MX, which hasn't seen much use lately, one *istDS with a cut-down MX screen in it as well as another *istDS with the OEM screen. Add to that a K100D with a KatzEye screen, same as the K10D screen, but without the OptiBright treatment.

Now, the only way to do any accurate type of comparison is to have two identical bodies, but with one body's screen without OptiBright, the other with. Alas, I do not have two identical bodies to compare. The *istDS bodies don't see much usage since I got the K100D and K10D. Besides, neither has a KatzEye screen.

So, that leaves us with the K100D with a KatzEye, but without OptiBright and the K10D, also with a KatzEye, but with OptiBright. Any comparison would be qualitative and not quantitative. I suppose I could swap the screen into and out of one body, but don't want to expose the prism housing too often. Just not worth the contamination possibilities.

My thoughts and what I firmly believe...I just love that split screen. Can't live without it. OptiBright, or not? It is my belief that, especially with the K10D, that the dynamic range of the data more than compensates for any minor exposure miscalculations. Of course, that is if one shoots RAW. Even if shooting JPEG, snapshots will be fine and there is enough leeway to play with the histograms of the images to generate a pleasing photograph.

Any exposure problems that I've had are when I use matrix metering or CWA in situations where spot would be more accurate.
02-26-2007, 02:06 PM   #3
Veteran Member
borno's Avatar

Join Date: Nov 2006
Location: md-usa
Photos: Gallery | Albums
Posts: 2,580
the k10d defaults to center weighted when using the aperture ring no matter what your metering setting is according to the book,if this helps you. Mine overexposes about 1.5 stops when using manual stop down with the aperture ring smaller than f4 or 5.6 depending on the lens with the oem screen, I was thinking of trying a *istds screen if this would cure it (some say it does) but I would rather get the katzeye so I would like to hear if someone has had this quirk fixed with a new screen too.
tb
02-26-2007, 09:45 PM   #4
Veteran Member




Join Date: Feb 2007
Location: Ontario
Photos: Gallery
Posts: 630
Original Poster
Volosong, Thanks for the summary and for putting your k10d out there! I'll definitely be ordering a screen...and am certainly leaning toward the optibrite to help keep things bright with stop-down metering and my tele lenses like the 300/4 SMC Takumar.

Katz seem to have done some really great things with these screens, I'll be happy to report my findings with stop-down metering after I have ordered and tested the screen.

Cheers!
Damian

02-27-2007, 03:19 AM   #5
Veteran Member




Join Date: Sep 2006
Location: Virginia Beach VA USA
Photos: Gallery
Posts: 1,364
You know, it is a funny thing, I had an awful time manual focusing my DS, and the Katz Eye screen was a life saver for me.

I don't seem to have the same problem with the K10. This camera just is much easier for me to MF with. I don't know why. For now I'm sticking with the OEM screen. I find I use spot metering quite often now, and don't want to mess up the metering.
02-27-2007, 05:35 AM   #6
Senior Member




Join Date: Sep 2006
Posts: 181
Not really answering your question directly, but I have the non optibrite katzeye for my k10d. Exposure seems to be very accurate, usind cwa (better than the DS with the factory screen). I shoot a lot with a manual focus 400mm f/5.6 and really wish I had got the optibrite treatment, even if there was some minor exposure discrepancies.
02-28-2007, 03:56 PM   #7
Veteran Member




Join Date: Feb 2007
Location: Ontario
Photos: Gallery
Posts: 630
Original Poster
I decided to go for the standard split and microprism w/Optibrite coating (no AF marks brackets). I'll report my findings with my takumars when I get everything up and running in a couple of weeks.

Thanks for all the help!
02-28-2007, 04:48 PM   #8
Veteran Member




Join Date: Dec 2006
Location: LI, NY
Posts: 313
QuoteOriginally posted by volosong Quote
I chose the split screen, microprism collar with the Pentax AF etched brackets, all topped off with the OptiBright treatment.

She put whipped cream on mine along with a bit of that dark chocolate hot fudge like they have at Carvel's.

Larry

02-28-2007, 06:04 PM   #9
Veteran Member




Join Date: Feb 2007
Location: Ontario
Photos: Gallery
Posts: 630
Original Poster
We have a couple of comedians on PF...well played sir :P
11-20-2007, 07:26 PM   #10
m8o
Veteran Member
m8o's Avatar

Join Date: Jul 2007
Location: 40-55'-44" N / 73-24'-07" W [on LI]
Photos: Gallery | Albums
Posts: 3,102
QuoteOriginally posted by d.bradley Quote
I decided to go for the standard split and microprism w/Optibrite coating (no AF marks brackets). I'll report my findings with my takumars when I get everything up and running in a couple of weeks.
Thanks for all the help!
D., sorry for digging up this old thread. But I figufed I'd ask as performing a search with the combo of your id and "optibrite" did not yield a post ... so what are your feelings/findings?

I've read that your use the split prism in various recent posts, but I am curious about your feelings of "OptiBrite". Are you happy and OK with the exposue error and compensation amount you need to apply using it? Also, by about how much do you have to apply compensation, and perhaps more importantly does that stay consistent across different aperture settings for the same lens, or do you have to adjust compensation based on what aperture you are at? (compensating is fine by me as I always do it, but I don't think I'd be happy if I have to change the amount I compensate by if opening or closing the lenses aperture. )

Hoping you see this thread was updated and read this (and offer a reply ). Thanx much,
-steve
11-20-2007, 08:12 PM   #11
Veteran Member




Join Date: Feb 2007
Location: Ontario
Photos: Gallery
Posts: 630
Original Poster
Hey m8o,

Yah, I have to admit that I'm not that impressed with the Katz and the K10D. The exposure compensation is directly related to aperture. On my 85/1.9 SMC, I usually use +1/3 to +2/3 around f1.9-f2.8, and work my way down with exposure compensation as aperture size goes down. By f8, I'm around -1.3-1.7EV, and f16-22 don't work in AV mode since I can't compensate enough for the overexpsure.

I'm thinking of switching to a DS screen. I don't know if opti-brite has much of an effect on exposure, but if I were doing it again I'd probably skip the treatment.

I don't think you'll find too many people who've tried both coated and uncoated versions...it's a little pricey to do both.

Although you get used to exposure compensation according to conditions. For example, I can usually set the compensation to -1.3EV or so on a bright day shooting outdoors because I know I'll be in the f5.6-f11 range. Or if I'm shooting at night I set it to the positive side so my shots at f1.9-f3.5 will come out right.

I think this is the weakest point of the K10D for me at the moment. Too much fiddling with knobs. Combine the exposure compensation with an m42 lens and you have a complicated "shotflow" :

1. open aperture.
2. compose and focus.
3. close aperture
4. check aperture value on lens if you haven't memorized the # of clicks to a given value
5. dial in exposure compensation
6. fire
7. review
8. rinse
9. lather
10. repeat

For the record...contrary to volosong's report above, you can't save a shot that has been auto-metered with the Katz+optibrite shooting anything below f5.6-f8 without proper compensation. Even in raw, it gets over exposed and more importantly SHUTTER SPEED drops significantly leading to motion blur. Yuck.
11-20-2007, 08:41 PM   #12
m8o
Veteran Member
m8o's Avatar

Join Date: Jul 2007
Location: 40-55'-44" N / 73-24'-07" W [on LI]
Photos: Gallery | Albums
Posts: 3,102
Thanx much ... that's exactly what I was hoping not to hear... Really not keen on having to keep a table in my head and changing compensation based on the apterture. I think I'm going to do the katzeye but w/o optibrite; not 100% yet but think so.
11-28-2007, 05:46 PM   #13
New Member




Join Date: Feb 2007
Location: Ohio
Posts: 2
In my experience

For what its worth... I have the KatzEye with split screen, microprism collar and Af exposure brackets w/o the Optibrite on both my K10D and *1st DS2. I shoot all SMC-A series lenses (9 in all) in manual mode using the in-camera metering set at center weighted. I love the screens on both DSLRs and could not manual focus without them. Using the SMC-A series lenses in the "A" setting and the DSLR in "M" mode allows me to meter-compose and still maintain open aperature focusing before the shot. It's the best of all worlds IMO.
11-29-2007, 07:10 AM   #14
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,396
Before I begin with my own comment, I have a question. Are we discussing the performance of K mount lenses and metering or ALL lenses.

The reason for the question is simple.

I have found that with K mount lenses (on a K10D), exposure is not linear as a function of F-Stop. I have characterized each of my lenses by using a relitively flat (color wise) target such as a block wall or paved road, with uniform lighting, and shot with what the camera metered for each apature. The results generally show that a fast lens, wide open, tends to under expose (f/1.4-f/2) perhaps by as much as 1 stop, then as you stop down, the camera meter tends to overexpose in the mid apatures (f/5.6 and beyonf, but over exposure generally peaks at about f/8 to f/11 at about +1.5 stops and then begins to tend back towards correct values at F/22 to f/32 (but it never quite gets there about +.5 stops high)

With the same lenses on my *istD the exposure is quite flat +/- 1/3 stop or better.

I do not have any fast (faster than f/2.8) KAF mount lenses to know if they also under expose. my f/2.8 70-200m seems quite correct on both the K10D and *istD
11-29-2007, 08:15 AM   #15
Not Registered
Guest




QuoteOriginally posted by Lowell Goudge Quote
Before I begin with my own comment, I have a question. Are we discussing the performance of K mount lenses and metering or ALL lenses.

The reason for the question is simple.

I have found that with K mount lenses (on a K10D), exposure is not linear as a function of F-Stop. I have characterized each of my lenses by using a relitively flat (color wise) target such as a block wall or paved road, with uniform lighting, and shot with what the camera metered for each apature. The results generally show that a fast lens, wide open, tends to under expose (f/1.4-f/2) perhaps by as much as 1 stop, then as you stop down, the camera meter tends to overexpose in the mid apatures (f/5.6 and beyonf, but over exposure generally peaks at about f/8 to f/11 at about +1.5 stops and then begins to tend back towards correct values at F/22 to f/32 (but it never quite gets there about +.5 stops high)

With the same lenses on my *istD the exposure is quite flat +/- 1/3 stop or better.

I do not have any fast (faster than f/2.8) KAF mount lenses to know if they also under expose. my f/2.8 70-200m seems quite correct on both the K10D and *istD
It is funny. Althought I didnt do an extensive test, some m42 lens that I have tend to underexpose at higher f without any split screen so it might not be a problem of the Katz-eye
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, f2.0, k10d, katz, lens, lenses, light, mode, overexposure, photography, spot, stop-down
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Katz eye for K10D/K20D (US/CAN) sabarrett Sold Items 7 06-02-2011 06:43 PM
For Sale - Sold: KatzEye Split Prism Focus Screen with OptiBrite for *ist D, DS, K10D, K20D eirual Sold Items 7 01-19-2010 08:34 AM
Focus screen: cheap chinese or shell out for Katz eye with Optibrite? virgilr Pentax Camera and Field Accessories 53 03-30-2009 01:04 PM
For Sale - Sold: Katz Eye w/optibrite for k100D and k200D lynch1234 Sold Items 3 01-06-2009 04:25 PM



All times are GMT -7. The time now is 02:12 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top