Aperture & Focal Length Analysis

Sigma 28-105mm f/2.8-4.0 Aspherical for Canon

06/02/2007 06:35:29 PM · #1

I have been looking to move to one or more faster (~ f/2.8) lenses for a while now and figured I needed a 17 - 50 or 18 - 50 mm focal range. Being a bit of a geek I then used Exif Viewer 2 to look at all of the photos in my current database to tell me what I really needed, based on past usage (about 5500 photos).

As these two graphs show, boy was I wrong!

In terms of focal length, looks like my "sweet spot" is between 40 and 120 mm. In terms of aperture I used f/2.8 18% of the time and f/8 26%. There is a slight bias at the 50 mm end as I do use the 50 mm prime a lot... does this mean I really need an expensive 70 - 200 f/2.8???

In figures:

12 - 39 mm: 10%
40 - 120 mm: 65%
90 - 200 mm: 41%

f/2.8 - 5.6 (inclusive): 46%
f/5.6 - 16 (inclusive): 60%

I guess my thoughts about the 17 - 50 were probably not correct as it is likely that a 50 - 150 or a 50 - 135 zoom.

Just thought I would share :-)

Carl

Rooster

Canon EOS-400D Rebel XTi

06/02/2007 06:38:16 PM · #2

Awesome thread! Very interesting. I am looking into getting another lens & this thread has been very eye opeing. thanks!

skylercall

Canon EOS-7D

Canon EF 70-200mm f/2.8L IS USM

06/02/2007 06:48:50 PM · #3

I should make a graph of my shooting habits but I really feel that I shoot between 2.8 and 3.2 almost all the time.

Canon EF 70-200mm f/2.8L IS USM

06/02/2007 06:54:18 PM · #4

Originally posted by skylercall:

I should make a graph of my shooting habits but I really feel that I shoot between 2.8 and 3.2 almost all the time.

I was a revelation to me that I shot the way I do. Most of the f/2.8 stuff probably comes from the Panasonic FZ-20 days where the lens was f/2.8 throughout but it is still an interesting reflection of how I have been shooting.

skylercall

Canon EOS-7D

06/02/2007 06:54:35 PM · #5

Okay, I am confused. Based on your study you do or do not feel that a fast lens would be necessary for your needs? It looks to me like you do need one because your second most used aperture is 2.8. Also, where is 1.8? Don't you ever use that?

Nikon AF Nikkor 85mm f/1.4D IF

06/02/2007 06:59:20 PM · #6

Originally posted by skylercall:

The analysis is not perfect by any means. As to f/2.8 I want some fast lenses for both bokeh and low light conditions as I have been asked to shoot a band live and not because of the analysis, although it did reinforce that I have used it a lot.

The analysis is a little faulty in that 2% of my shots were at f/2 or below, implying that I used f/1.8 - 2 for about 100 shots, which feels about right. However, this has increased recently as I appreciate the sharpness of the prime and have started to use it more.

Hope this clarifies things a little.

pawdrix

Nikon D700

06/02/2007 07:07:08 PM · #7

I think you might shoot differently if you bought good glass that was ALL, one big "sweet spot"...top to bottom, side to side, through and through.

You may be looking at this in all too technical a way. I assume you'd want to shoot well in all ranges since different things call for different treatment.

I've had fun sticking to one aperture for a whole day (unless some subject required a change) and getting the feeling for that zone, so to speak. Groove in different zones. It forces you to look in a certain way which is a great exercise.

Get good glass, have fun...

Message edited by author 2007-06-02 19:08:30.

Canon EF 24-70mm f/2.8L USM

06/03/2007 04:18:13 AM · #8

Originally posted by pawdrix:

Yeah, trying to shake off this geek thing is not easy :-) I have actually used just the 50mm prime for a day and it was an education - and kind of fun. At a family gathering a week or so ago I used the 18 - 200 a lot and then switched to the 50 mm indoors and with flash - and the results were stunning! People's skin had a real feel about it and using the aperture to control dof was an education.

And to be honest, if you analyse what you have done in the past, you can only be sure of what you have done, not what you will do!

It was so much easier when all I had was a 35 mm, a 50 mm and a 135 mm on my Minolta SLR. The real problems started when I got my first zoom, a 70 - 200 mm and started to get lazy... Now there is a thought :-)

dwterry

Canon EOS-1D Mark III

06/03/2007 09:05:30 AM · #9

Here are two other thoughts to keep in mind:

1) Most lenses are at their sharpest when they are stopped down one or two stops from wide open. Therefore, for an f/2.8 lens, that means f/4 is where the sweet spot starts. Meanwhile, if you are buying glass that is f/4 to f/5.6 at it's widest, you're sharpest images aren't going to occur until f/6.3 or f/8. Thus, with a slower lens, you're giving up a lot of light for a sharp image.

2) I don't know about the Nikon, but most of the Canon cameras have a focusing system which is more accurate with a lens that is f/2.8 or below. You don't have to shoot at f/2.8. The glass just has to be f/2.8 at it's widest in order to activate the cross sensor focusing.

In both of the above thoughts, the idea isn't that you necessarily shoot wide open, but that fast glass offers you advantages (even if you stop down from wide open) that you simply can't get with a slower lens.

Message edited by author 2007-06-03 09:32:18.

diablo2097

Apple iPhone 5s

Canon EF-S 18-55mm f/3.5-5.6 II

06/03/2007 09:23:15 AM · #10

out of curiousity, does this include P/S users? As i'm not sure, but doesn't the DOF differ in P/S because of the difference in sensor size?

Would be interesting to see a comparison based only on SLR users...