[BrianR]

@brianr How did you calculate the distance from the subjects? I know it is possible if you know the height of the subject, but I am wondering how did you get those numbers exactly...

Here's a calculator:

Jason's Log: Camera Lens Calculators

I made the guess that ~1m of the subject was in the frame. It's probably less, but plus or minus a foot or two wouldn't have affected the result that the DoFs are approximately equal.

[normhead]

Some good points Norm, but let's not assume that just because people can handle and enjoy a discussion on the technical side of things that they've forgotten about the artistic/aesthetic side. They're not mutually exclusive - and understanding of the technical can consciously be used as a means to hit your artistic vision.

They are not mutually exclusive, unless you make them that way. If you discuss the technical quality of lenses without discussing the aesthetic values, that's kind of like discussing the internal workings of an internal combustion engine, and car park, instead of learning to drive.

but let's not assume that just because people can handle and enjoy a discussion on the technical side of things

I don't assume much. I would say, lets not assume that because are discussing the technical side of things, they have a clue about actually taking a photograph. The two are not mutually inclusive.

and understanding of the technical can consciously be used as a means to hit your artistic vision

.

You need to know the technical side of lens design, but only as it applies to your artistic vision. The technical must inform and therefore include the artistic value. Talking technical without references to the artistic value is not going to improve you as a photographer. It just doesn't magically happen somehow.

[BrianR]

They are not mutually exclusive, unless you make them that way. If you discuss the technical quality of lenses without discussing the aesthetic values, that's kind of like discussing the internal workings of an internal combustion engine, and car park, instead of learning to drive.

I agree the aesthetic is important... that's what this whole thread is about with a dive into the technical side of what happens at different distances, focal lengths, etc. Knowing what happens and when gives you info about the toolkit you have for creating your art.

The technical should enable the artistic (and in some cases feed it), and certainly not overshadow it.

[MadMathMind]

Wow, a lot of good information in this thread. I plan to read it in depth this weekend. I am sure I will have follow-up questions and comments.

An original concept, using an FA 31 to fix the unflattering sharpness of a Sigma!

I really like my Sigma for objects but I've come to not prefer it for people. It has a rendering which is a bit...hyperreal. Its edges are unspeakably sharp and a bit abrupt. It makes people pop out of the frame a bit like a pop-up book. That's one thing I don't like. But the sharpness is a bit too much for portrait shots. You can see pores, mistakes in makeup, and razor stubble. It's really unbelievable at times.

That works well in those super-reality photos, though. But for ordinary people, it's a bit too much. I think something with a bit more smoothness and dreaminess would be a bit better. Fortunately, I now have the legendary FA31 in my clutches too. I'm not giving up on my Sigma, though, since it works wonderfully for objects.

[stevebrot]

Distortion

Gosh I hate that spooky-looking series. My apologies if they are your work. It has been published multiple times on this site, each time to support the notion of feature exaggeration traceable to focal length. What it shows is that you get different perspective based on distance. All of the examples were taken at different distances. The series also shows that the photographer favored a much tighter composition with the longer lenses.

Is it safe to assume that all of the series were captured to the 35mm FF format?


Steve

[stevebrot]

It's maybe worth pointing out here that Depth of Field and background blur are related but not the same thing.

That is very true.

[stevebrot]

@brianr How did you calculate the distance from the subjects? I know it is possible if you know the height of the subject, but I am wondering how did you get those numbers exactly...

I would guess that he estimated the height of the model and worked backward from there.


Steve

[BrianR]

Is it safe to assume that all of the series were captured to the 35mm FF format?

Yes, they're taken on a 35mm. I posted the link to the original back on page 2 which explains the changing distances between shots and more: Untitled Document. I don't like hot linking to it because it is, as you say, spooky

[Lowell Goudge]

snip,,,,,,,@brianr How did you calculate the distance from the subjects? I know it is possible if you know the height of the subject, but I am wondering how did you get those numbers exactly...

Look at my post on the first page too

Image size ='subject size x focal length / distance

You can estimate the subject easily enough, I use 30cm for head shots, 1 meter for waist up / seated shots and 2 meters for a standing subject. Then think about your working distance and you get focal length

[MadMathMind]

What he is talking, although commonly referred to as perspective distortion, is actually nothing to do with "perspective" at all. what the distortion is all about is magnification ratio.

consider, that lens magnification, in simple terms is the following

Magnification = Image size / Subject size = focal length / distance
...

This was a very helpful post! You correctly guessed that I like numbers, so I found this explanation very intuitive to my brain's wiring.

Wide angle lenses can be used to make women's legs look longer when shot from close to the ground, and men's shoulders look broader when shot from slightly above. So the perspective thing is very real, but whether it is a problem or not depends on who your subject is, and what (face, head/shoulders, 3/4 body, or full body) you are shooting.

Right. I've used perspective distortion to effect a couple times. I find that you need a really wide angle lens and focus very closely. I do plan to use some of it with the subjects I will be shooting. The legs thing may come into play as well, but I definitely will use perspective distortion with some of the props the cosplayers use.

The internet age's standard example of headshots vs focal length: Untitled Document

Nothing I've shot has ever looked like thise short focal length shots in the link, fortunately.

It's the same with a building, if you stand right in front of the door, you only see the door, but with a wide angle lens you can stand on the door mat and fit in much of the building, but the building will look more natural photographed from across the street with a longer focal length. Buildings don't complain about their doors looking too big, however.

I've noticed that architecture is incredibly unforgiving when it comes to focal length and angle of shot. It doesn't take much to get an utterly hideous shot.

Actually if you take the picture from the same distance using all three lenses at f/5.6, the DOF will be identical. Of course, you will then have to crop the 35mm and 70mm images considerably to get a similar subject framing as the 200mm, but once you do that, you will get the same background blur. <-- Edit: I think I might have overstated this.

Below are two photos taken from the same position using identical camera settings. The only differences are the focal lengths (35mm and 55mm) and the fact that one was cropped to the same field of view as the other.

It is fairly obvious that the perspective is identical between the two. It is also obvious that the DOF is quite different despite both being shot at f/11.Edit: Actually, the lens should not really make a difference.

The lens does make something of a difference. There's a big difference in the Sigma 18-35 and FA31. It's not just quality of bokeh, either. The FA31 just obliterates backgrounds while the Sigma blurs them.

The focal length, of course, makes a huge difference. At the short end of the Sigma, even if you focus close at 1.8, the bokeh is not that strong. It becomes much stronger as you reach the long end of its range.