[MJB DIGITAL]

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Hey guys. I havent really looked much into focus screens before. But I was reading over on FredMiranda and someone said that you can get, for a 1series canon, a focus screen that shows the 8x10 crop of an image.
WOW that would be useful.

I'll start some research, but has anyone heard of that for pentax. It's something would I be begging for change to buy.....
want one want one want one...

[pschlute]

I am not with you ? How can the focus screen affect the size of the image ?

[MJB DIGITAL]

I am not with you ? How can the focus screen affect the size of the image ?

no
there is, superimposed within the FOV, a bounding box which designates where the crop lines are for an 8x10 crop. and that doesnt necessarily mean <i>size</i> but rather dimensions.
for instance,
if, using this screen, you composed with a 16x20 in mind, that would work as well provided you had the pixel density/depth to print that size

not sure if i am explaining this right....i have never even seen an aftermarket focus screen...

[roy]

it explained it perfectly..
there are also screens that have a tic tac toe like bounding box that represents the rule of thirds..

[vinzer]

no
there is, superimposed within the FOV, a bounding box which designates where the crop lines are for an 8x10 crop. and that doesnt necessarily mean <i>size</i> but rather dimensions.
for instance,
if, using this screen, you composed with a 16x20 in mind, that would work as well provided you had the pixel density/depth to print that size

not sure if i am explaining this right....i have never even seen an aftermarket focus screen...

Your explanation's dead-on. No worries.

You could look at Katz Eye Optics' site if you're interested in such screens. They could customize screens to your liking, and it seems to be well-received among a lot of photographers (Pentaxian or otherwise).

[MJB DIGITAL]

whoa SWEET!!! thanks guys

btw does everyone here know about the new Zeiss K mount lenses?

[MJB DIGITAL]

OK i checked out the site and placed an inquiry

now, im reading something about 'optibrite' that is supposed to enhance the brightness at small apertures

does this mean that the focusing screen stops some light?
i dont really get it.

do you lose a little light through the screen the same way you would lose some light through a flash diffuser?

thanks
mitch

[Bostjan]

Light metering on any given camera is calibrated for a specific screen. If You were to change the screen for another one, You can expect that You have affected the metering (i.e. power of light reaching the light meter will be different under different screens).
Solution: usually a + or - 1/3 or 1/5 EV change (easy to do on a DSLR)

Hope this helps,
Bostjan

[roscot]

Most people who got the Optibrite screens regretted the decision, as it effects exposure readings more than the standard screen. I've got a standard Katz Eye with the split image and micro screen collar on my DS. Exposure is within 1/3 of a stop using multi segmented and center weighted meter modes. Spot metering is toast though, due to the split image.

[vinzer]

OK i checked out the site and placed an inquiry

now, im reading something about 'optibrite' that is supposed to enhance the brightness at small apertures

does this mean that the focusing screen stops some light?
i dont really get it.

do you lose a little light through the screen the same way you would lose some light through a flash diffuser?

thanks
mitch

In the old days when AF was non-existent and split-screens reigned supreme, there always was an issue wherein one-half of the split circle went dark when the lens' aperture was set at a certain point and beyond (I think this starts at 5.6 and smaller apertures). It then becomes hard to get focus owing to one-half of the circle going dark.

I think the Optibrite treatment cures that problem, although as others have said, to the detriment of the accuracy of the light meter reading (the sensor is located past the focusing screen, as far as I know).

I don't know much about the China-made screens if they still exhibit the dark half-circle problem (mine's en route in a few days), but you could ask others. A lot of forum members invested in a split-screen, either from China, Haoda, or Katz Eye.

[Deni]

I have the screen from china. It does start to get dark at f/5.6 and unusable at around f/11.

As far as I remember optibrite for the katz eye just makes the view brighter. The one that cures the darkening of the circle is the katz eye plus.

[igowerf]

I bought a screen for my *ist DL the other day off eBay. It's this one:
Split Image Focus Screen for Pentax DL K100D - (item 140139765785 end time Jul-24-07 17:55:25 PDT)

They say that it's made from a K1000 screen and it even has the extra tab to help orient the screen. I'll report back after I get it and install it.

[Matt Miller]

I use the Katz Eye split prism with optibrite in my K10D. I absolutely love it. My slowest lens is f/4, so I don't know if the optibrite was necessary. The screen is a dream to use when manual focusing, and does not affect auto focus at all. It does affect exposure slightly with some lenses, but that’s easily corrected with EV adjustment after a test shot. Simple. I went with pano grid lines, to help me keep horizons level. It feels like a different camera with the Katz Eye, so much better. Highly recommended.

[Deni]

I bought a screen for my *ist DL the other day off eBay. It's this one:
Split Image Focus Screen for Pentax DL K100D - (item 140139765785 end time Jul-24-07 17:55:25 PDT)

They say that it's made from a K1000 screen and it even has the extra tab to help orient the screen. I'll report back after I get it and install it.

That's the same screen I have for my k100d. It's a fine screen but half of the circle starts t get dim after f/5.6.

[MJB DIGITAL]

so, theoretically, if an optibrite screen is 'clearer' than a regular penax screen, i would have a brighter viewfinder. then my meter would read like another 1/3 stop high.

both of my pentaxes read read 1/7 - 1/3 high making me underexpose if i set the meter dead on