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08-17-2013, 01:45 PM   #1
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Poll: what what speed does your zoom lens have at intermidiate focal lengths

I am interested to know what speed do different zoom lenses have at intermidiate focal lengths.

Just try your zoom lenses and say what focal length is minimum for each 1/3 stop.

For example: I have Bigma 24-135, it has:
F2,8 at 24mm
F3,2 does not show
F3,5 at 31mm or so
F4 at 50mm
F4.5 at 100mm

Please try yours and post results.


Last edited by Casion; 08-17-2013 at 01:50 PM.
08-17-2013, 02:06 PM   #2
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QuoteOriginally posted by Casion Quote
I am interested to know what speed do different zoom lenses have at intermidiate focal lengths.

Just try your zoom lenses and say what focal length is minimum for each 1/3 stop.

For example: I have Bigma 24-135, it has:
F2,8 at 24mm
F3,2 does not show
F3,5 at 31mm or so
F4 at 50mm
F4.5 at 100mm

Please try yours and post results.
You mean that you have a Sigma 24-135mm? "Bigma" is the nickname för Sigma's 50-500mm lens
08-17-2013, 06:14 PM   #3
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My DA50-200WR is f/4 to 70mm, f/4.5 to 140mm then f/5.6
Sigma 28-90 macro: f/3.5 to 32mm, f/4 to 40mm, f/4.5 to 55mm then f/5.6; and 1:2 macro is at 90mm f/5.6
Sigma 100/300 (slow): f/4.5 to 170mm, f/5.6 to 250mm then f/6.7
08-17-2013, 06:26 PM   #4
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QuoteOriginally posted by Casion Quote
I am interested to know what speed do different zoom lenses have at intermidiate focal lengths.
Why? When I care a lot about maximum f-stop (fully open), I typically use a zoom lens with a constant f-stop. Most of my zoom lenses with variable apertures at different focal lengths need to be stopped down to achieve good resolution, so I don't need to pay much attention to their maximum f-stop.

08-18-2013, 02:39 AM   #5
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QuoteOriginally posted by Phii Mii Quote
"Bigma" is the nickname för Sigma's 50-500mm lens
Didn't know that it was for one model only.

I noticed that Sigma lenses are ont compact in general so I thought that this word can be used for all Sigma-s.


QuoteOriginally posted by nater Quote
Why? When I care a lot about maximum f-stop (fully open), I typically use a zoom lens with a constant f-stop. Most of my zoom lenses with variable apertures at different focal lengths need to be stopped down to achieve good resolution, so I don't need to pay much attention to their maximum f-stop.

1) I do not care for sharpness anyways.
2) There are not so much autofocus fixed-speed lenses on the market.

jimr-pdx, thanks!

Also very interested in these ratings for 70-300 F4-5,6 and 18-200s.
08-20-2013, 07:29 AM   #6
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Correct me if I'm wrong, but I've always been of the opinion that with variable aperture lenses the max. available f-stop decreases continuously(!) when zooming to the long end, and not in steps. Therefore, the values changing in discrete steps as displayed by the camera are just the effect of rounding up or down.
08-20-2013, 07:38 AM   #7
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QuoteOriginally posted by Casion Quote
I noticed that Sigma lenses are ont compact in general so I thought that this word can be used for all Sigma-s.
The "Bigma" nickname is also used on the cheaper 150-500mm, but they get bigger. Much bigger.



That's a constant-aperture lens, f/2.8 all the way to 500mm. Of course, I don't have it, and I wouldn't even if I had $26,000 to burn.
08-20-2013, 08:01 AM   #8
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QuoteOriginally posted by scratchpaddy Quote
The "Bigma" nickname is also used on the cheaper 150-500mm, but they get bigger. Much bigger.



That's a constant-aperture lens, f/2.8 all the way to 500mm. Of course, I don't have it, and I wouldn't even if I had $26,000 to burn.
I know it's off topic, but with a lens that size, I think I'd just use a telescope and get even more telephoto.

Anyway, I always thought the Bigma was for the 50-500 mm Sigma lens (or possibly any Sigma that goes out to 500 mm). Thus the "Big". A smaller zoom Sigma is just a Sigma.

As for the aperture, I do believe the aperture shown is just a function of the digital camera's "resolution" in reading f-stops (with regard to whether you are adjusting in 1/3, 1/2, or 1-stop increments). If the camera is wide open, it will actually be some value that matches up with the fixed diameter of the lens and the actual focal length. It would seem that it might be easy to actually calculate what the real aperture is at any focal length and see how well it matches up with the display. I'm sure if someone is bored they could do that math quickly in Excel.

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