I looked it over and it looks great!
My light meter reads different EV values depending upon the ISO setting when in EV mode. I believe the "standard" EV is referenced to ISO 100. Would that be the case for the EV values as they affect exposure times in the spreadsheet? In other words, should I set the ISO to 100 before taking an EV measurement with the meter and using the sheet?
Thanks,
Don
That's an interesting idea!
I tried it and found the lateral distortion of my inexpensive scanner was pretty bad. Plus, the pinhole mounting prevented contact of the copper foil with the scanner bed. Backlighting the pinhole with a portable light table, inverted seemed to give the clearest results. I scanned at 2400dpi in close zoom and enlarged further in Photoshop so the pixel blocks could be seen. I boosted the contrast to reduce the fuzzy boundaries and drew a circle using the vertical axis to set the diameter, as there seemed to be less distortion. I counted the pixel blocks and came up with 29.
That's 29/2400 of an inch or .012 inch x 25.4 = 0.304mm for a pinhole with an advertised 0.3mm diameter. That's a pretty good result.
Best,
Don
View attachment 193388
View attachment 193389
Some meters only display EV for ISO 100 and then relying on your use of the calculator dial for other ISO. One example is the Pentax spotmeter. Some call this value LV. With your meter the Minolta Auto IVF the EV is for the ISO set and since you will set the ISO according to your film speed no further calculation is needed.
Some meters only display EV for ISO 100 and then relying on your use of the calculator dial for other ISO. One example is the Pentax spotmeter. Some call this value LV. With your meter the Minolta Auto IVF the EV is for the ISO set and since you will set the ISO according to your film speed no further calculation is needed.
4x5 super-wide angle pinhole image taken with a Graflex Super Graphic view camera using my exposure spreadsheet, detailed here. The image was taken directly onto graded #2 enlarger paper and reversal processed. The end result is a pseudo-tintype, as the image is one of a kind and reversed left to right.
0.3mm pinhole, 88.9mm pinhole to film plane distance, yielding an effective aperture of f/296.3. Exposure was 3 minutes and 3 seconds with an average reflected exposure meter reading of EV8.9. The paper was metered at ISO 3. The processing of the paper is almost identical to that used in old-school black and white photo booths.
Excellent! That's a very impressive result. Remembering the early part of this thread, I will admit bringing reversal processing into the mix likely wants more precision in exposure than I'm used to worrying about. Printing from negatives offers an easy path to compensate minor exposure variations in the original negative. (Some day you have nothing to do) it might be interesting to do some bracketing at fractional stops just to get a practical feel of the effects of exposure precision (or perhaps you already have).
Nice. Certainly has a historical feel.
Are we looking at the final product, or an intermediate step? If intermediate, and if scanning would be the route to the final print, does a negative or positive original make any difference?
I think pinhole and paper reversal go together really well.
You're right Dave, the exposure is a little more critical ( at least the way I've been doing it -- I'm using a different process than Don is )
But I have to admit, even if it's subconscious, the left-right reversal bothers me and for me it is a drawback. I often feel strongly that I like a composition flipped one way but not the other, even if there's nothing obvious like backwards letters. There is a painting of Mt Tamalpais in my dentist's waiting room.. and the light in the painting comes from a direction where the sun can never be... and it gives me an uneasy, almost queasy feeling when I see it. When I look at my reveral paper negatives, I get a similar feeling.. "just doesn't feel right"...
I guess if it bothers me enough, I might try sticking a 45 degree mirror in front of one of my pinholes and see what happens....
The end result is a pseudo-tintype, as the image is one of a kind and reversed left to right. View attachment 203749
Actually, the image posted isn't reversed left to right:
View attachment 203847
View attachment 201991 I remember back in darkroom times when the creator of a dial told to adjust something during photocopy-work. but i dont remember exactly. its about distortion during copy-process.
2. i was shooting my unknown pinhole of my clack 6x9 with APS-C and Luminar-handhold.... counter checked by looking through with peakloupe. its 0.29mm on a clack-6x9 curved filmplane. will now calculate the real fstop.... no images yet taken.
81.48mm on the center-side and 74.22mm in center if filmplane would be flat... now calculate pls. which is eff. aperture?
I learned regarding sharpness for pinholes exact hole in correspondence to FL is not so evident but for zoneplate and sieve it is.
NB: aupremierplan has now flexible pinholes.
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