Lenses

[William W]

Hi Boab,

Yes.

That was exactly what I was doing - I was being accurate for the benefit of the OP: that's why I included Camera Format which jcuknz also missed out.


And that's also why I questioned your use of the phrase "at a given focussed distance".

Because that to me was confusing and I don't understand what that phrase means in the context of the DoF remaining the same, when using DIFFERENT Focal Lengths ? ? ?

***

Also I was not suggesting that 'picking nits' was bad thing.
Clarifying the situation for the OP is good.


WW

[xpatUSA]

#14 Since there is a marked difference in the size of the ornament beside the ruler, which is different also, I cannot see how you are following what I said... for a given image size DoF remains the same irrespective of what focal length lens you are using.

I am not sure what we are arguing about becuase it is a fact of life beyond discussion.

I'm bowing out of this discussion - my 'humble pie' post was in full agreement with your statement above. Even a cursory examination of the ruler scales would have shown my agreement, in that the depths of field (about two inches) were approximately the same at each focal length.

Just to make it perfectly clear: my original statement was wrong. Your statement is correct, albeit delivered a rather condescending manner.

As to why the 'ornament' is not equally sized in each shot, that's the best of 10 or more trips back and forth to an non-airconditioned camper in mid-afternoon on a 107 deg F day here in East Texas.

As to the ruler being 'different also' at the 3 widely different shooting distances required for equal framing of the focal zone, could somebody more au fait with the subject of perspective please confirm that the ruler aspects in my images should indeed differ . . . or have I got that wrong, too? (hint: was trying to keep the angle of the ruler to the lens about the same, to more properly show the depth of field on the ruler scale).

LOL . really I think you are hopping along on one leg, you should try layers and see how brilliant an idea they are by whoever came up with the concept. Ordinary layers and layer masks ... truely wonderful tools for us to use I use layers in connection with almost every shot I take into editing ... "life would end if I didn't have it, it didn't start until I finally worked out how to use it"

When I said "I don't use layers", I meant it. I was not 'LOL' joking. My quality goal is simply to compose and take a shot with minimal post-processing. Sharpness and color accuracy are important to me and I enjoy powerful but simple tools, such as found in RawTherapee.

[jcuknz]

My apologises to you Ted, no offence intended. I think if the ruler was inclined at 30<45 degrees against a wall it might work better. On my monitor I couldn't read the rulers. But I am very glad not to be in the States at the moment it must be extremely enervating. And dangerous judging the Arizona tragedy.

"At a given focus distance" is just as clear to me as "With a given image size" ... in the first the DoF would be quite different depending on focal length becuase the image size would also be quite different. I really don't see the relevance of Camera format since if working with a cine camera with 15,25 and 75mm lenses or an SLR with 55,90, and 270 the result would be different in detail but the same in principle.

People accuse me of simplifying things to the essentials, a key feature in good photography, while others add in the irrelevant

As for the hyperfocal balarny ... well .. completely irrelevant in my photography