What's your favorite internet falsehood on photography?

[darr]

This is way pre-internet. I recall 60+ years ago when I first got interested in photography I'd occasionally hear people assert with great authority that lenses made before World War II were not "color corrected". Have a hunch they were confounding anti-reflection coating with color correction.

David

I recall being advised in the past that it's best to avoid using older single-coated lenses with color film.
This advice appears to align with the points you've made.
I've had the opportunity to use a few single-coated lenses, and the primary difference I've noticed is a reduction in contrast.
When used as creative tools, these lenses can impart a unique character to images, provided that I keep their limitations in mind.

Thanks for your post, David.

[Alan Klein]

I'm guessing you want an example of figuring your actual f/stop instead of a bellows extension factor.

Say you have a 210mm lens at f/16. At infinity, 210/16 gives an entrance pupil of 13.125mm.

Now say you rack the bellows out to 350mm. Just divide 350 by 13.125 to get your f/stop at that bellows extension: f/26.66.

(Personally, I'd round it off to 350/13 to get f/26.9, and call it f/27.)

Or you can go with the traditional method of dividing, squaring, and multiplying.

Thnaks for the sample.

1. Why f16?
2. Wouldn't you need a large opening for loss of light, not smaller?

[jnantz]

that's for below the equator, above the equator it's open up 1 stop

[sharktooth]

Thnaks for the sample.

1. Why f16?
2. Wouldn't you need a large opening for loss of light, not smaller?

It means if the lens is set to f16, your "effective" aperture is now f27, so you're going to have to compensate by using more exposure time. There's really no free lunch here. You have to do a few math calculations no matter what, unless you're a mathematical savant.

[darr]

... There's really no free lunch here. You have to do a few math calculations no matter what, unless you're a mathematical savant.

Try explaining EV numbers and exposure combinations that can be altered yet give the same value to someone who does not "get the math."
I was told I was making it up because they could not grasp the math.

[freecitizen]

" You can always go back and photograph it again " .

[Mark Sawyer]

Thnaks for the sample.

1. Why f16?
2. Wouldn't you need a large opening for loss of light, not smaller?

1. f/16 was an arbitrary choice and a pretty commonly used f/stop. The math works for all f/stop values.

2. I'm presuming the photographer chose that aperture based on the depth of field (or lack thereof) desired. We're using tripods anyways, so go for the aperture that gives you what you want, and let the exposure time fall where it may.

[gypsydog]

This favorite from this morning, an article comparing the quality of digital vs full frame digital vs large format. The author states that he didn't use an actual 4x5 to make the image but rather photographed the cameras ground glass, goes on to say its the same thing as making an actual large format film image. Wish I had saved the link, it was hilarious.

[jnantz]

1. f/16 was an arbitrary choice and a pretty commonly used f/stop. The math works for all f/stop values.

2. I'm presuming the photographer chose that aperture based on the depth of field (or lack thereof) desired. We're using tripods anyways, so go for the aperture that gives you what you want, and let the exposure time fall where it may.

mark ..

years ago someone posted a calculation device that seemed to work well for him..
it had to do with making believe the MM of hte lens was an Fstop, so a 90mm lens would be f9, extending the bellows to 180mm would be like f16 ( well a little more )
and it's 1(+) "stop" difference. .. seemed a lot easier than multiplication or division to me. I dont' do macro work so I don't know if it is actually as useful as it seems
but for a lot of people the less math the better. LOL

[Alan Klein]

1. f/16 was an arbitrary choice and a pretty commonly used f/stop. The math works for all f/stop values.

2. I'm presuming the photographer chose that aperture based on the depth of field (or lack thereof) desired. We're using tripods anyways, so go for the aperture that gives you what you want, and let the exposure time fall where it may.

Sorry your explanation does not help. I understand f/16 was an arbitrary setting initially. But what does f/27 mean in question #2 and how is it appled. You don;t change the aperture to f27 do you?
That would decrease the light when you need more. Please clarify.