Canon LTM Appropriate settings for a 28 mm lens?

Canon M39 M39 screw mount bodies/lenses
Coldkennels said:
...what focal length, in what format, and based on what circle of confusion? What print size is it expecting?
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It is for 107.8mm lens for a 6' x 8' print. What did you expect? Did you expect a chart that pertains for the discussion? Oh, my God, man, you are so out of step. Circle of confusion?? This thread, Bucko.
 
boojum said:
It is for 107.8mm lens for a 6' x 8' print. What did you expect? Did you expect a chart that pertains for the discussion? Oh, my God, man, you are so out of step. Circle of confusion?? This thread, Bucko.
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The point I and a few others are making is that asking for "the appropriate settings for a 28mm lens" is like asking for the length of a piece of string. What type of string? What do you need it for? Even shoelaces come in different lengths.

As I've said multiple times: test. See what works for you. Don't just regurgitate or blindly follow information that might not be relevant to or appropriate for the results you want.
 
Freakscene said:
CoC is for engineers, not photographers.
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Genuine question, though: with CoC being tied to print size and the expectations of the size of a standard print changing from the 1920s to the modern day, surely that'd mean the "depth of field" standards should change at the same time - in other words, the engineers calculating the depth of field scales on lenses would/could/arguably should have altered them slightly to reflect the larger prints that became popular later on.

That might explain why the Canon 28mm Serenar's depth of field is slightly more "permissive" than the VC 28mm from the 2000s. Maybe.
 
Coldkennels said:
Genuine question, though: with CoC being tied to print size and the expectations of the size of a standard print changing from the 1920s to the modern day, surely that'd mean the "depth of field" standards should change at the same time - in other words, the engineers calculating the depth of field scales on lenses would/could/arguably should have altered them slightly to reflect the larger prints that became popular later on.

That might explain why the Canon 28mm Serenar's depth of field is slightly more "permissive" than the VC 28mm from the 2000s. Maybe.
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I don’t know any engineers who do depth of field scale design, but probably. Certainly lenses that looked allright, and depth-of-field settings that looked ‘sharp enough’ for a folding medium format camera whose output would mostly have been contact prints would not cut it on 35mm, let alone a digital sensor. But the scales are notably different on those lenses and cameras.

I usually assume the very largest print I might make, typically 1x1.5m, close viewing distance and 20/20 vision if I am calculating the CoC or depth of field.

But the critical thing with focus is to _look_. It seems obvious, but not many people write down or remember their settings, then look at their files or prints and assess if they are sharp enough where they want them to be. Even fewer have controlled enough technique to isolate sources of unsharpness. @Erik van Straten makes beautiful 18x24cm silver prints. My guess is that what works for him won’t work if you want to make 100x150cm prints. But looking is really critical, whether you are making movements with a view camera, setting a lens for depth of field from the scale, or focusing.
 
boojum said:
It is interesting to see folks post numbers for 28mm depth of field. I posted a link to several 28mm depth of field charts in my post, the second IIRC, which have been pretty much ignored in preference for discussion of what it is and how it works. I was misguided in thinking that the request for DoF info was cut and dry. LOL

It seems the OP asked what time it is and has been told how to make a watch.
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To paraphrase Terry Pratchett - "Give a man a the time and he will know the time for now. Tell a man how to make a watch and he will know the time for the rest of his life."

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To add a bit of actual content, I almost never "stretch" the DOF scale to infinity for snapshots. I'd rather have the DOF reach a bit closer, too. So for 28mm I usually set it at 7feet (at f/8 since I want my shutter speed to be high-ish) thereabouts. This gives enough depth of field for the context (distant buildings etc) to be still readable. But also gives me good focus from 4 feet to about 20feet.

I mean that's why we scale focus, right? It's not exactly necessary for landscapes...
 
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Problem is photography also involves science and technology a lot more than the other two (although I'm sure there's a lot of science behind painting and sculpture, too). Using your eyes is important - but you also need to engage the thing hiding behind them, too.
 
Coldkennels said:
Genuine question, though: with CoC being tied to print size and the expectations of the size of a standard print changing from the 1920s to the modern day, surely that'd mean the "depth of field" standards should change at the same time - in other words, the engineers calculating the depth of field scales on lenses would/could/arguably should have altered them slightly to reflect the larger prints that became popular later on.

That might explain why the Canon 28mm Serenar's depth of field is slightly more "permissive" than the VC 28mm from the 2000s. Maybe.
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The usual 'reference print' size of 8x10 inches works fine even if the average size of prints has increased over the decades since DoF was defined. The reason it was chosen as the DoF reference is that 8x10 inch is a 'large book' size and is about the largest size print that can be comfortably viewed in its entirety held in your hands and seen as sharp with normal 20/20 vision (whether uncorrected or corrected). Larger size prints are usually viewed from a somewhat greater distance, even today, and since perceptual sharpness is dependent upon the acuity of the human eye, at viewing distances greater than 14 to 20 inches the acceptably sharp CoC tends to be larger.

Of course, any calculation of DoF is/has been/will be always a 'reference guideline' not a hard and fast rule or statement of fact. It a calculation designed to give a notion of the approximate range in which you can get a satisfactorily sharp looking image for any given focal length/distance/aperture combination. What is 'satisfactorily sharp', or perceived as in-focus, depends to some degree on what the subject matter is as well as how well the lens is focused and the aperture is selected.

Summing up, there is little real meaning to the notion of "appropriate settings for a 28mm lens" without the overall context of what the photographer's intent for a particular subject and scene might be. In my first post on this thread, I took the OP's statement of what he/she was used to using with a 25mm lens to articulate settings that would give a similar result for a 28mm. That was just a set of assumptions leading to a similar result that would be "appropriate" in the same circumstances when the 25mm lens settings worked, but it certainly wouldn't be an appropriate setting for all circumstances.

G
 
I don’t have a blanket rule. It depends on the scene. Even with a 28 there may be a figure in the distance I want sharp, and I will focus on that, and the nearer rock and a few daisies are going to be slightly out of focus, which is nearly always tolerable as they’re large enough in the frame, being close, to be perfectly recognizable. This is why I like infinity lock lenses. So often I’ll set focus to just before the lock engages, about 20m. Landscape photographers with wide angle lenses and tripods use hyperfocal tables. Street photographers with 28s probably use two distances preset.
 
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Freakscene said:
There is no such thing as a point or place of focus; only blur circle.
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Sorry Sir, I just thought communicating an idea was more important than pedantry, sometimes you have to decide when to say something even if you know it, and when not. I will however continue to adhere to common understandings in future as everything else unless entirely relevent is just 'showing off', don't you think?
 
SWB said:
Sorry Sir, I just thought communicating an idea was more important than pedantry, sometimes you have to decide when to say something even if you know it, and when not. I will however continue to adhere to common understandings in future as everything else unless entirely relevent is just 'showing off', don't you think?
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I’m not a sir, and I’m not showing off. Sorry.
 
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