bellows factor app

[Rod Klukas]

You need only carry a pocket inch tape measure.

When doing close-up work and your subject is closer than 8 times the focal length from the lens you will need to compensate for the extension. Take the focal length of the lens in inches and the length of the bellows in inches. Make the measurements unit the f-stop and judge what is the difference.
I.e. 210mm lens = 8"(approximately}

With a 16" extension of the bellows the extension factor would be 2 stops.
210mm=8"=F8 16"extension =F16
The difference between F8 and F16 is 2 stops.

You should compensate as much as possible by shutter speed and deal with the fraction of a stop with the aperture.

Hope this helps.

Rod

[maltfalc]

Just use f-stop inches. For an 8 inch lens (“f8”) open 1 stop at 11” (“f11”) and 2 stops at 16” (“f16”). Substitute f-stop cm as needed.

this is by far the easiest, fastest method and the very last comment made two years ago. there was no need to resurrect this thread.

[Drew Bedo]

I can't believe that this thread is still open.

[Renato Tonelli]

I can't believe that this thread is still open.

Generally speaking, most are no longer comfortable doing seemingly simple match calculations. How many elementary school students do you think have memorized the multiplication table?

On a practical note: years ago I bought a used 5x7 field camera and the previous owner permanently attached a very thin adhesive ruler in both inches and mm - nice option to the ruler; I have been looking for the same for my 4x5 but have not found one.

[Heroique]

Generally speaking, most are no longer comfortable doing seemingly simple match calculations. How many elementary school students do you think have memorized the multiplication table?

Me, I love math, and I mean geometry, algebra, calculus, and more! You should have seen me shine in elementary school. Good thing I played sports, or I think I would have suffered abuse from the jocks.

The love of math continues to this day. To be sure, I may be the first one to claim in this forum, right here, right now, that AA’s appendix in “The Camera” (with all those formulas, fractions, and equations) is one of my favorite sections!

However, when it comes to bellows correction, I fall into the humble K.I.S.S. camp.

That is, I don’t worry about bellows correction unless the distance to my subject is closer than 10x my focal length.

When this happens, I’ll simply add 1/2 stop for every 25% increase in bellows extension (beyond infinity).

Example: Let’s say I’m using my beloved Fuji A 240mm/9. 10 x 240mm = 2400mm (or 2.4 meters). So when my subject is closer than 2.4 meters from the camera, that triggers “bellows compensation” in my mind. And I’ll eyeball how much my bellows length has gone beyond infinity, and if necessary, add a suitable amount of light, usually in 1/2-stop increments.

So maybe there's hope for the elementary kids you mention who'd rather avoid complex math but still be LFers. ;^)

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Adding exposure for bellows extension is rare for the type of landscapes I do, but whenever that moment comes, one extra thing I sometimes struggle to remember is to add yet more exposure for any reciprocity failure.

[maltfalc]

Generally speaking, most are no longer comfortable doing seemingly simple match calculations. How many elementary school students do you think have memorized the multiplication table?

On a practical note: years ago I bought a used 5x7 field camera and the previous owner permanently attached a very thin adhesive ruler in both inches and mm - nice option to the ruler; I have been looking for the same for my 4x5 but have not found one.

https://www.amazon.ca/s?k=adhesive&r...ref=nb_sb_noss

[Renato Tonelli]

https://www.amazon.ca/s?k=adhesive&r...ref=nb_sb_noss

Thank you. I will check it out.

[John Layton]

I consider myself a proactive person...and therefore I will proactively refuse to use WhatsApp...so there!

Edit: I actually prefer to do all of this stuff in my head...because that's pretty much where I live these days...

[sharktooth]

I made a table of bellows extension factors, and printed it out on a sheet of paper that I can fold up and carry with me when needed. That works great if I remember to take the sheet with me.

On the other hand, most people will be carrying a phone with them all the time now, so it is a convenient place to keep infrequently used info. Saying that, there's really no reason to actually use an app, when you can just put the info in your phone as a text file, or as a picture.

My significant other, doesn't even have internet access, but she does carry her phone around with her to make calls (whoda thunk). I was amazed when she took out her phone to take a picture of the grocery store flyer near the store entrance. She used that flyer picture to assist with her shopping, with no need to download an app. I was impressed that she was making a "smart" use of her phone without needing a data plan.

There's a lot of useful stuff you can put on your phone that doesn't need to be in app form to be useful. You just need to be smart about it.

[Tin Can]

I don't drive anymore

When I did I always calculated my MPG in my head while driving

Not as easy as you might think

No notes, pencil or paper and you must be driving