Tom’s World – 04APR2026 – Photography – Depth of Field Preview

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TomD

DOF-Preview
DOF-Preview

The picture I posted is of an old late 70’s era lens for a film camera. It looks a little grungy but I haven’t touched it in well over 20 years.

This lens has a feature that all lenses had at the time but not any more and I don’t know why. It is called “depth of field preview”. This is set up at f4. See the 2nd ring out from the body? It has the straight vertical orange line with the little 4, 8, 11, 16 on each side of the vertical. Notice that the lens is now focused between 10 and infinity (meters). Now look down at the 4’s on each side of the orange vertical. They show that the camera will be focused from around 10 meters to infinity. That explains your shot above.

The DOF preview also tells you that if you were shooting f16, you would be focused from roughly 4 meters to infinity.

To this day I miss this feature. But I guess that it requires too much thinking (read any) for today’s public.

UPDATE:

I should mention that this camera is a Canon AE 1 from sometime in the late 70’s. It was an auto exposure (AE) but you still got to set ISO and shutter speed, and not to mention focus vis a split image distance finder.

(Quick historical aside: split image was the principle optical range finding method for most naval gunnery prior to radar. If you’ve ever seen the zagged warship camouflage paint schemes from WWI and up to mid-war WWII, the purpose was to defeat or eliminate the effectiveness of split image range finding. It gives you no clear planes to match up.)

I had a main camera before the AE1, a Nikon F1, a pure manual camera though it did include a “match needle” for setting shutter and f stop. Before match needles, we had to carry a light meter on a cord around our necks. Things were definitely manual but that meant that you had to have an understanding of all of the elements involved and how they related.

I learned to shoot with my Dad’s single shot 1934 depression era .22 bolt action. No magazine. In order to shoot, you had to, open the bolt, take a single .22 round, insert it in the chamber. close the bolt, pull back the firing pin, aim and fire. Just like having to set all the elements of a photograph, this little production meant that the shooter had no instant backup and had to think about about what he was doing, and understand.

I remember trying to teach my stepson how to shoot with a Ruger 10-22, an autoloader. The 1 lesson was a disaster. With all the easy backup rounds, he had no motivation to absorb the elements that go into a successful shot and just start spraying to little effect. All further lessons until he was a fundamental shooter were with Dad’s old Winchester single shot. Or as I was later pounded into us in the Marine Corp, “sight alignment, trigger squeeze”. I already knew but I did qualify Expert using a M14.

Successful photography is a balancing lesson between a number of variables. Until you learn those variables, one by one and how they interrelate——–

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TomD
TomD
4 months ago

I should mention that this camera is a Canon AE 1 from sometime in the late 70’s. It was an auto exposure (AE) but you still got to set ISO and shutter speed, and not to mention focus vis a split image distance finder. (Quick historical aside: split image was the principle optical range finding method for most naval gunnery prior to radar. If you’ve ever seen the zagged warship camouflage paint schemes from WWI and up to mid-war WWII, the purpose was to defeat or eliminate the effectiveness of split image range finding. It gives you no clear planes… Read more »

Tregonsee314
Tregonsee314
4 months ago

I remember helping my dad set up for shots with his Mamiya C330 TLR, no match needle, he had a Gossen Luna Pro light meter (considered one of the best of its day) that I still have (although it is inoperable as it uses batteries that are no longer common). My job was to run to various spots and get the values from the light meter. Similarly, he had a flash meter that you used to make sure the flash was providing enough light and to figure out what exposure you were going to use as the Light meter just… Read more »