Gear advice (Canon)

[AtSea]

Not "can make" -- DOES make. No if's or buts about it. Not even close.

I've already conceded that software can make an image sharper. I can say software "does" make an image sharper if that helps? I think one other issue that creates, though, is in certain cases where adding that sharpness can degrade the image in other ways - especially if the image already has noise as a result of low light. In most cases (and maybe this is old-school thinking), you want to have the image as good or as sharp as possible straight out of camera. Again, we can talk about how subtle the difference can be but it's somewhat arbitrary unless we're comparing specific lenses. I was making a generalization, but I *STILL* think it stands: Lenses that start with larger apertures get sharper, as subtle as it may be. We don't have to argue over this any longer, I think we both know where we stand on the issue.

If I were to list in order all the things necessary to gain a competitive edge, an F2.8 lens over a F4.0 would be pretty close to the bottom.

And that's completely fine! A lot of people shoot with an 85 1.2, and a lot of people shoot with a zoom lens. A lot of people have taken apart a camera and put it back together again, a lot of people don't know how to access their menu. I understand that a 2.8 and 4.0 are less and less relevant with the improvements in electronics, algorithms and manufacturing of sensors - but to ME, those improvements are still there.

[AtSea]

I disagree. That's a commonly put phrase, but I don't believe that it is about the DoF as many times as people think that it is.

For example here is a Chart for DoF for three typical Portrait Shots made with 135 Format Camera, although not listed the DoF for F/4 falls very close to half-way between F/2.8 and F/5.6. As can be seen there is not a really appreciable difference in the DoF for the Full Length Shot, considering the DEPTH of a person’s body, certainly less practical difference for the Half Shot and less again for the Head Shot:



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No, actually both of the original points that were made, don’t seem to stand: and that’s my point . . .

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I agree, but I suggest that in mostly all cases it is NOT about the DoF (which was first stated) but about the quality and texture of the OoF Background Blur – and that is a different animal to DoF.

This is not a pedantic point for the sake of pedantic points: but it is about defining why Available Light Portraiture appears different (and often identifiably different) when comparing for example the 135/2L shot wide open up against the 70 to 200F/4 shot wide open.

This can be so with the 24 to 70/2.8 and the 24 to 105/4, both shooting wide open, also.

And it is also so when using an F/2.8 lens at F/2.8 and then comparing it used at F/4, and there is often quite a noticeable difference when this test is performed.

Bok Atkins has a ‘Blur Calculator’ which puts numbers on these visual factors.

WW

Hey William, your points are totally valid. More often than not, I am mistaking the two terms. I think it's one of the most widely-spread myths in the photography world.

Background blur is a huge issue (which again, also improved by a large aperture - we can discuss to the degree of that as well - I'm sure Colin would chime in here).

I shoot a lot of environmental/full-body portraits, and when I referred to DoF, I was accurately referring to the fall off of sharpness, if you will. I like to open up to 2.8 to isolate the person from the background as much as possible - and this has everything to do with Depth of Field. The quality of the background blur is an added characteristic of the aperture. Your chart does not negate this.

Both of my original points *do* still stand, and it is getting somewhat pedantic.

[AtSea]

Just because this is fun, #1,#3 @ F4.0 and #2,#4 @ 2.8

Her hair starts to become visibly softer in #2, so I'm most sure about that one. Answers?

As you say, it's not discernible to the eye at such sizes. I never disagreed with that.

Just one addition to this - I regret bringing it up at all in this context. It's the last thing any beginner should be thinking about/worrying over. It's a discussion that should be had when someone has been shooting for years and is considering spending $1000 vs $2000 on a 4.0 vs 2.8 - so I'm sorry to have taken the thread in this direction.

[William W]

. . . The quality of the background blur is an added characteristic of the aperture. . .

Indeed. But that is only part of the story. It is also characteristic of the aperture used relative to the maximum aperture available; also the lens itself; and the aperture blades; and the background to subject distance; and the Focal Length of the Lens; and the texture of the background and the lighting on the background . . .

And that is my point - the quality of the background blur is NOT about the DoF, it is related to the DoF but it is not defined by or a product of the DoF.

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Maybe an example will assist: the quality and texture of the background blur will be DIFFERENT if one uses an F/2 lens at F/4 and then an F/4 lens at F/4, for the SAME SHOT and compares and contrasts the two shots.

- BUT -

The Depth of Field will be the SAME for both shots.

WW

[AtSea]

Indeed. But that is only part of the story. It is also characteristic of the aperture used relative to the maximum aperture available; also the lens itself; and the aperture blades; and the background to subject distance; and the Focal Length of the Lens; and the texture of the background and the lighting on the background . . .

And that is my point - the quality of the background blur is NOT about the DoF, it is related to the DoF but it is not defined by or a product of the DoF.

***

Maybe an example will assist: the quality and texture of the background blur will be DIFFERENT if one uses an F/2 lens at F/4 and then an F/4 lens at F/4, for the SAME SHOT and compares and contrasts the two shots.

- BUT -

The Depth of Field will be the SAME for both shots.

WW

Well put, we don't disagree.

[William W]

. . . these points and discussion about separating DoF and Background Blur are relevant to the OP: as he was/is considering an F/2.8 vs. an F/4 Lens and these may be relevant elements of his choice – or someone else’s choice, who is reading the thread.

WW

[ajohnw]

Going back to the OP's first few posts it seems he has a 24-105mm and wants to shoot street and uses a full frame camera and is looking at the 24-70 2.8. They are an interesting pair of lenses and actually in some ways are better used on a crop camera - more even resolution across the frame and less vignetting etc.

Personally I feel he would miss the 70 to 105mm range so might be better of sticking with that and using his primes if needed but am inclined to agree that in practice F4 to F2.8 isn't much of a jump really. All that can be said on that score is that at F5.6 the 2.8 is probably generally better than the F4 at F5.6. Does this matter for many shots - most likely not.

In this situation it might pay to look through shots taken and see what focal lengths have been used and make a decision based on that. This sort of range isn't all that well covered. The next zoom jump is usually to something like a 28-300mm at high aperture and I always think why not something similar, constant F2.8 and 24-150mm rather than the massive jump.

As Colin points out ISO can make up the difference and the 6D is pretty good in that respect in relation to noise. Blur - many people produce shots with an unhealthy degree of it. In terms of making subjects stand out it's best when it's subtle and no distracting tones in the background. The shots that have been posted illustrate several factors that relate to this area from maybe may as well black the lot out to ones where it works but not to the extent it might have given different backgrounds. Bill's in particular illustrates that but any one who does look at will see the lady first and under the circumstances the far background has to be as it is - the gent in the foreground though is still inclined to be un noticed initially.

John
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[Colin Southern]

Just because this is fun, #1,#3 @ F4.0 and #2,#4 @ 2.8

Her hair starts to become visibly softer in #2, so I'm most sure about that one. Answers?

Well done ...

... but you got them all wrong

The first was F5.6
The second was F4.0
The third was F2.8
The forth was F4

Hopefully you get my point that a 1 stop DoF difference isn't anything that particularly makes or breaks an image.

PS: Because I figured some people would cheat, I swapped the exif data around on a couple of them

[AtSea]

Well done ...

... but you got them all wrong

The first was F5.6
The second was F4.0
The third was F2.8
The forth was F4

Hopefully you get my point that a 1 stop DoF difference isn't anything that particularly makes or breaks an image.

PS: Because I figured some people would cheat, I swapped the exif data around on a couple of them

Haha.

[Colin Southern]

Haha.

I wasn't joking.

[Glenn NK]

I am using a Canon 6D. The other thing that is making me hesitant to switch to the 24-70 is that it has no IS... Why Canon? Why?!

OK, now that I know which body you have, I think your yearning for the 24-70 is just gear lust.

Canon knows a few things about photography, and they've been pairing the FF 5D series bodies with the 24-105 in a kit for good reason - it's an excellent fit. On a crop body, not quite as useful unless you tend to use longer FL's.

Other than the build, the reason I really use the 20-105 so much is the IS - to me it's much more useful than one stop. If you're in some tight spots doing landscape work, the 24-105 is very versatile. I took my TSE24 Mark II to the Oregon coast two years ago with the intention of making really good use of the tilt feature. I had trouble composing the scenes I wanted with the fixed 24 mm FL (simply couldn't walk far enough in either direction), gave up and used the 24-105.

As someone else pointed out, double the ISO (it works most of the time unless you're in really poor light).