Law of Diminishing Returns (lens $$ again)

[steven_darche]

Hi all,

 

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I've spent quite some time reading archived posts in this and other camera forums, and it seems lens quality for the money questions are by far the most common. Indeed, many people are hoping to get something for nothing, or even trolling for approval on a decision they've already made.

 

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However, there are those like myself that are coming into photography from other hobbies, and our expectations are more realistic. Just as it's true that you get what you pay for, it is also true that there is a law of diminishing returns. Furthermore, for many people there exists a product that may have weaknesses, but excells exactly where they need it to.

 

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Since my first post, I have tried out many lenses, and have made some purchases which are working out quite well for me so far. I bought 24mm and 50mm primes for my landscape, building, and indoor existing light photography. All I need are some lenses in the longer focal lengths.

 

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This is where things get sticky, and I need some help. Primes in the telephoto range are mucho expensive; Sigma 105 + Canon 200/2.8 = $968. For that price, I might as well get an L zoom. But before I pay for a 70-200 2.8 L, I want to make sure I'm not overbuying (price = $1150) for my needs. I have a few alternative scenarios I want to throw by everybody:

 

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1) Since I really want to be able to throw backgrounds out of focus in outdoor portraits, I get the Sigma 105/2.8 prime. Having a fast lens for portraits, I'm free to go with a 100-300 USM to reach out more. My demands are greatest in my landscape and portrait shots; I'm willing to put up with SOME softness and loss of contrast in my long distance "critter" pics from a tripod if it gets me closer. But is the USM too far below the L, or only slightly? Is it on par with the better "mid end" zooms such as the 28-105? Will I notice with 4x6 prints? Price = $588

 

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2) I go with the Sigma 70-200/2.8 and I can always pick up a 2X teleconverter so I can reach out to 400 which is the farthest reach of all my options. Price = $749 ($918 with telecoverter)

 

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3) Get the Canon 70-200/4L, which relatively light (and cheap) with very high optical quality. But is f/4 wide enough to blur a distracting background? I know that question has no absolute answer, but from your experiences, do you find it is most of the time? Or do you use the 2.8 frequently? Price = $579

 

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I'm also open to any good ideas that I may not have considered.

 

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Thanks for bearing with me!

[hung_james_wasson]

Hi Steven,

 

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I would suggest to you the Canon 100-300mm f/5.6L EF. It is half the

price of the 70-200mm f/4L, and is said to be tack sharp. It's not

USM, so does not focus as fast, and there's no full time manual

override.

 

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For $330 US, vs the $660 for the 70-200mm f/4L, or $1130 for 70-200mm

f/2.8L -- you've got nice optics for a steal. I think you'd have to

go with a high grade third party TC (multi-coated, multiple elements)

if you needed further reach (a 1.4x would only cost you one stop, and

give you a 140-420mm f/8 [about the same as the 70-200mm f/4L with a

2x TC, better actually] & a 2x would give a 200-600mm f/11 [very

dark, & the image quality might be pretty poor]) -- I don't think the

Canon TC's will work with it.

 

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Might this fit your bill for only one zoom lens to go along with your

stable of primes?

[j._o.]

The good news is that one of your concerns has an absolute answer:

background blur is determined by the physical diameter of the lens's

aperture, if all else remains equal. So a 105/2.8 has about the same

blur potential as a 50/1.4, both of which are a good deal behind a

200/2.8.

 

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None of the telephoto options are perfect for all purposes.

(Certainly not for blur. 70mm and f/2.8 wouldn't be descibed as

"fast" by any means.) The option I would choose is the 70-200/4 and a

portrait or macro lens, depending on your taste.

[damond_lam]

Dear Stephen,

 

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Why do you want Sigma lens? Optically Canon lens is better. Tokina is

between Sigma and Canon. This is my general feeling after reading

tons of user reviews.

 

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There are three top quality Canon telephoto primes which are

reasonably priced:

1/ 85/1.8 USM $345 or 100/2.0 USM $399

2/ 300/4L USM (Non IS version) around $800 new if you search around

 

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I have the 100/2.0 (very sharp) and the bokeh is nice. I own Noctilux

50/1.0 and use 75/1.4 Sumilux (Leica M) very often so I know a bit

about bokeh (blurred background).

 

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Get a 2x teleconverter then you have 200/4.0.

 

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I care about optical quality and weight so relatively inexpensive

Canon primes fit my bill.

[stephen_ratzlaff]

Steven,

 

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I have both the 200mm f/2.8L and the 70-200 f/4L. Both are sharp,

with the edge going to the 200mm f/2.8. I'd consider the 200mm f/2.8L

along with any 100mm macro lens (most macro lenses regardless of make

are pretty sharp). The 70-200 f/4 L is a good lens, but you can at a

later date use Canon's 2x converter with the 200mm f/2.8 to give you a

decent 400mm f/5.6 and still have autofocus capability with your EOS

camera with the center focus point.

 

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The 200mm f/2.8L is physically shorter than the 70-200 f/4L but a bit

bigger in diameter (bigger front element, f/2.8 remember). Really for

portraiture, f/2.8 and 200mm, plus somewhat close focusing, gives

very, very shallow depth of field so f/4 or f/5.6 would most likely be

used anyhow. These will still blur the background quite nicely.

 

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Regards

[steven_darche]

Thank you all so much for your input. By all suggestions, a 100mm

prime is in my future as my "bokeh" happy portrait lens regardless of

my zoom choice. The only reason not to buy a 100mm prime would be if

I got a 70-200/2.8, but I think I've pretty much figured out it's a

mismatch with my needs at this point. I'll buy my third prime, the

last relatively affordable prime. The only thing I have left to

decide on is my first question; the zoom! But if I'm not expecting it

to do portraits at 100mm, then that eases my aperture hunger

considerably. I must say that Hung's suggestion of the 100-300/5.6L

is a very tempting morsel indeed.

[hung_james_wasson]

Yes, getting an L series lens for the price of a consumer zoom! I've

even managed to talk my wife into it...just waiting for that tax

refund check! :-)

[derrick_morin___fallon__ne]

Steven,

 

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I think you will be pleased with the 100 as a portrait lens. I

bought a 100 2.0 for portraits a year ago and I love it. It does a

terrific job with sharpness and backround blur. I am beginning to

like my new 200 2.8L for portraits too; be careful with whatever zoom

you buy - you may find yourself leaning toward longer focal lengths

for your portraits!

 

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Derrick

[michael_lopez3]

I'd like to reinforce a point made earlier, in passing. The Law of

Dimishing Returns applies optically as well as monetarily, in the case

of teleconverters. A 2x converter gives significantly poorer results

than a 1.4x converter. Even if the converters are optically perfect,

the 2x doubles the size of any defects in the main lens, while the

1.4x enlarges the defects' size by "merely" 40%. In addition, the 1.4x

cuts the effective aperture by 1 stop (only half the light going

through the main lens reaches the film), while the 2x cuts the

effective aperture by 2 stops (only one quarter of the light going

through the main lens reacheas the film). In short, 1.4x converters

are significantly less harmful to image quality.