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kukkurovaca PRO 7:37pm, 28 September 2008
And would they be willing to do some comparison shots at f/5.6?

I noticed when looking back at my 180 v. 55-200 comparison that I didn't see a substantial difference in light transmission at f/5.6, but that I did see one at f/11, so I'm wondering if the 55-200 is maybe not really delivering the light transmission at f/5.6 that it should be.

However, I can't really test this, since I don't have any other modern-coated lenses in the same focal range.

Hmm. Maybe my 105mm f/2.5 K would work. I think that might be multicoated, although not modern coatings.
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David Van Chu PRO 9 years ago
You could always go to your local photo store :P
princessbren2006 9 years ago
I own the 55 - 200 lense and use it all the time
Ala-Ala ni Batman! [deleted] Posted 9 years ago. Edited by Ala-Ala ni Batman! (member) 9 years ago
I own also 55-200 before. no regret!
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kukkurovaca PRO 9 years ago
Please don't start posting 55-200 sample images.

There are many threads about the 55-200; in this thread, there is a specific question about comparison of light transmission between the 55-200 and other lenses when shooting at f/5.6
Orbmiser 9 years ago
kukkurovaca

Give me some conditions? I have the 55-200vr and the Tamron 17-50 f2.8 and could shoot both at 50 and at 55 at f5.6?

If that would help? Daytime? Indoors? Subject? give me the optimal type subject to maximize results?
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kukkurovaca PRO 9 years ago

Give me some conditions? I have the 55-200vr and the Tamron 17-50 f2.8 and could shoot both at 50 and at 55 at f5.6?

If that would help? Daytime? Indoors? Subject? give me the optimal type subject to maximize results?


Anything should work, subject-wise, so long it's the same thing with the same amount of light. What I'd like to know is how much light is getting through each lens -- in other words, do you get the same level of exposure/histogram/etc. with each lens, and if not, how much compensation would be needed to get them to match.
basegrinder Posted 9 years ago. Edited by basegrinder (member) 9 years ago
this question reminds me of an eariler debate

was it this group where the little scuffle was?

some folks say that f/stop is a ratio bla bla bla light transmission has NOTHING to do with the front element bla bla bla

so your 55-200 with its 48mm or so front element at f/8 would be same as the the LBT in arizona.... with its 11,800mm element at f/8


remember that one? I do. boy scientists sure are dumb building those huge glass telescopes when all they need is 1 1/2" of glass to get the exact same light transmission.
basegrinder 9 years ago
Oh I gotta run out but I think there is a website I saw once that was testing "actual f/stop" values
Orbmiser 9 years ago
Okey Dokey I should be able to get something up tomar!

Will see what I can find with good light and detail. Do you need shots at one-stop under over? D80 or D40?
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kukkurovaca PRO Posted 9 years ago. Edited by kukkurovaca (admin) 9 years ago
basegrinder --

Well, theoretically, light transmission should be the same. In practice, flare can substantially reduce light transmission, as I discovered when I compared my 35mm f/1.4 AIS to my 35mm f/2 (no multicoatings).

Today I was looking at my old 180 v. 55-200 comparison set, and I noticed that the 55-200 has a notable advantage in light transmission at f/11...but not at f/5.6, despite having modern coatings while the 180mm f/2.8 does not.

This makes me wonder if perhaps the 55-200 is not only delivering sub-par optical performance when shot wide open, maybe it's also delivering sub-par light transmission...
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kukkurovaca PRO 9 years ago
orb --

Thanks! You don't even need to worry about detail; all I'm interested in is the exposure level. Either camera will work, and over/under is strictly at your discretion. : )
Orbmiser 9 years ago
Okey dokey...
Eddie Barksdale 9 years ago
This is a different example, but looks at the same issue.


A 50mm f/1.8 D (china) at f/5.6 vs a 18-55m f/3.5-5.6 at 50mm and f/5.6. Guess which one is the 50mm.
Orbmiser Posted 9 years ago. Edited by Orbmiser (member) 9 years ago
Sorry kukkurovaca but is a wash today for me. Maybe tomorrow...

Made 7 trips to the john between 4am-7am with that which shall not be named. keeping me up and just now getting up at 4pm PST.
Mike Lichtenwalner 9 years ago
I'm gonna guess the top one is the 50mm.
kaixiang 9 years ago
Erm... the bottom image is obviously brighter but I do detect a little more blur on the adidas text in the bottom one as well, making me suspect camera shake from a lower shutter speed. Could you confirm whether you were shooting in M or A mode?
Eddie Barksdale 9 years ago
It's a focus error, because the bottom one was autofocus. I used a tripod on selftimer in Manual mode. If you stack them, you'll notice the framing changed even though it's the same focal lenght, and there's a difference in the distortion pattern as well, but you would never noticed that just looking at them like this.

Mike is right, top is the 50mm.
EXIF for top is:
Camera: Nikon D40
Exposure: 0.125 sec (1/8)
Aperture: f/5.6
Focal Length: 50 mm
ISO Speed: 200
EXIF for bottom is:
Exposure: 0.125 sec (1/8)
Aperture: f/5.6
Focal Length: 50 mm
ISO Speed: 200

Enough conformation for you?
kaixiang Posted 9 years ago. Edited by kaixiang (member) 9 years ago
Thank you for the confirmation. I apologize if the question i asked sounds stupid.

Now that you mentioned it I do realize there is quite a bit more background on the left of the bottom image. The bokeh is much more pleasing for the 50mm f1.8.

And thanks again for doing the test, you've made me love prime lens more =)
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David Van Chu PRO 9 years ago
I thought the 50mm was the bottom one at first.

...that's sad :P
Eddie Barksdale 9 years ago
I agree David. It's an old design, but it's so much simpler!
kaixiang 9 years ago
In practical use, I find myself preferring the 50mm wide open than the 18-55mm VR when shooting handheld in low light, so I hope thats a little consolation.

Sometimes the simple stuff just works better.
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kukkurovaca PRO 9 years ago
Okay, I did a comparison between the 55-200 and the 105mm f/2.5 K. The K is multicoated, but not with modern coatings; this would be 70's-era coatings.

I just checked the histograms, and the 55-200 has the advantage. Not by a lot -- it looks like maybe 1/3 of a stop, maybe even less.

I'd still like to see a comparison with something at the long end, though, so if someone has a 70-200 f/2.8 (any brand) and a 55-200 VR, or even a coated version of the 180mm f/2.8 or 200mm f/4, I'd like to see it.

I'll post the test shots later this evening, probably.
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kukkurovaca PRO 9 years ago
Eddie Barksdale, do you have the original images, and/or when you checked the histogram, did you make a note of how large the difference in exposure was. 1/2 a stop, 2/3?
M A R K fresh 9 years ago
kukkurovaca, why does the other lens have to be of a similar focal length?

f/5.6 is f/5.6... if the focal length is longer it's still the same amount of light.
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David Van Chu PRO 9 years ago
So the images are similar?
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kukkurovaca PRO Posted 9 years ago. Edited by kukkurovaca (admin) 9 years ago

kukkurovaca, why does the other lens have to be of a similar focal length?

f/5.6 is f/5.6... if the focal length is longer it's still the same amount of light.


Different focal lengths have different tendencies to flare, you can't set up the comparison shot the same way without changing the contents of the scene or moving the camera, etc.

Also, with zooms, light transmission may vary with focal length. And actual light transmission is not always the same at f/5.6 -- that's the whole point of this exercise.
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