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06-23-2018, 02:37 PM   #1
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Original P645 question about focus screens.

Recently delved into the MF world with an original Pentax 645 and a couple lenses from a fellow Pentaxian.
Have taken some excellent photos with it and need to take more but been busy with needed work around the homestead.
While I have had the 645, it came with a split screen and then went to a regular matte screen.
Reason is that my eyes suck and looking through the viewfinder is like looking at a frosted image with the 645.

Been reading reviews of the 645n's and owners state that the viewfinder is brighter.
Got to thinking, why would it be brighter ?
Different focus screen design ?

Well I took a chance on one for sale here for $12.
What could I lose ?

Received it today and knew from photos of the focus screen that modifications would be in order.
Had to nip off the vertical and horizontal locating tabs but the screen fits perfectly in the 645 holder.

Tested it out with both of the lenses.
Night and day difference.
The frosted image of the old 645 focus screens to the 645n clearer screen.
I can actually see what I am taking a photo of without that dark frosted image.

Now comes the question.
Are their any things to consider in metering with a brighter focus screen ?
Or will the camera just do it's thing like it always does ?

Thanks;
Clarence

06-23-2018, 07:07 PM   #2
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QuoteOriginally posted by c.perkins Quote
Are their any things to consider in metering with a brighter focus screen ?
Or will the camera just do it's thing like it always does ?

Clarence
I have both the 645 and the 645N. I suspect the 645 viewfinder may be darker on your camera due to the fresnel screen. I have the original split center focusing screen and it is marginally darker than the 645N.

The metering will not be affected by the focusing screen. A brighter screen will just help you manually focus. The biggest factor is the lens. With my 75mm f/2.8 prime, the screen is considerably brighter than, for example, with a 55-110mm f/5.6 zoom.

Correction: I'm not 100% sure, but I believe I was incorrect in my earlier statement. So if we're comparing the OEM 645 screen and finder vs. the OEM 645N screen and finder, the brightness difference is not an issue.

However, the light meter sensor on the 645 is probably up in the pentaprism and would be affected by a brighter focusing screen if, for example, you went from an OEM screen to a non-OEM Beattie screen. In this case, I would use an external light meter to compare the readings off an 18% grey card on the 645 vs. the light meter reading and if there is a difference, set an exposure compensation. The last thing you want is to underexpose your negs if the brighter screen fools the meter into thinking there is more light than there actually is.

Last edited by Alex645; 06-24-2018 at 01:37 PM.
06-24-2018, 12:25 PM - 1 Like   #3
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Thank you Alex for the information.

It is what I thought but had to ask.
Reason is a while back was reading something about a brighter/clearer focus screen change on I believe a digital DSLR(could have bee a film camera, I don't remember).
They were talking about having to drop a stop or two to compensate for the new focus screen.
I could not make any sense out of it cause to me, why would it matter, the amount of light is the amount of light.

Well, at least the next time I take the 645 out I will be able to see the image better to focus more accurately.
Which was the whole intent of this experiment.
Will see what happens in the next couple rolls.

Thanks;
Clarence
07-02-2018, 11:35 AM   #4
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Just dropped off a roll of Portra 800 rated at 500 to "The Darkroom".
Half the photos with the A80-160 and the other half with the A120 macro.
Using Auto mode as I have done since owning the camera.
Only shot one roll so I can determine if my focus is accurate before I move on.
Hope it works out cause like I said the image in the view finder is like night and day.

Will keep you posted.
Clarence

07-03-2018, 09:29 AM   #5
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QuoteOriginally posted by c.perkins Quote
Now comes the question.
Are their any things to consider in metering with a brighter focus screen ?
Or will the camera just do it's thing like it always does ?
I have the Pentax 67ii and a few 67ii "bright" focusing screens for macro and telephoto shooting. Pentax did warn in the 67ii focusing screens brochure, to be careful when metering with the Pentax 67ii AE prism when using these bright screens. However I have not noticed any affect when using the bright screens, so hopefully the same applies to the 645 format screens.

Phil.
07-04-2018, 02:22 PM   #6
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Thank you Phil;

Should be getting my film back sometime next week.
Waiting patiently.

Clarence
07-06-2018, 06:30 AM   #7
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QuoteOriginally posted by c.perkins Quote
Just dropped off a roll of Portra 800 rated at 500 to "The Darkroom".
Why 500 and not 800?
07-06-2018, 12:55 PM   #8
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QuoteOriginally posted by leekil Quote
Why 500 and not 800?
A lot of C41 films handle over exposure very well, in fact, some prefer it to metering it at box speed. Lately when I shoot Portra 160, I meter it at 100, and it comes out great.

07-06-2018, 12:59 PM   #9
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Leekil;

More or less an experiment really.
Last roll I shot was Fuji Pro 400H rated at 200 and developed at box speed.

A lot of what I have read about 120 film is that it will take a stop or two of over exposure pretty well.
If it lifts the shadows a bit I'm happy.

Reason I say that is when I am post processing my digital images in Lightroom you will find me on that shadows adjustment on almost every photo.
I like a hint of what is in the dark

Clarence
07-08-2018, 10:13 AM - 2 Likes   #10
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Downloaded my photos from The Darkroom last night and viewing them this morning.

Focus turned out very good overall, some a bit off and some spot on which is typical for me cause all my shots are hand held.
Note to self: start using the tripod already, will ya.

The clearer focus screen from the P645n did make a difference for me to get in focus a bit quicker.
The original screen was a back and forth issue usually a half dozen times before settling and taking the photo.
New screen was quicker with maybe back and forth 1.5 to 2 times and settled to take the photo.

As far as the exposure of the images.
All turned out great, none under or over exposed.
LR histogram were all in the middle area.
This was Portra 800 rated at 500.

With what I have used so far with this camera my favorite has been Ektar 100 and Portra 400 second.
But the next load going in is Portra 160 to try out.
I do still have a roll of Fujifilm Neopan Acros 100 to test out also, will probably save that for a rainy day.

I will post some photos in the MF photo tread later.
Clarence
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