Did I just buy the wrong lens?

HckySo

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Apr 9, 2006
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I wanted a cheap solution for a beginner wide-angle lens so I ended up ordering this $70 sigma lens yesterday. Today I just couldn't figure out why it was so cheap. It says somewhere in the details that it works with Digital cameras but in the title it only says "Nikon AF". I have a Nikon D50 and I'm wondering if when I get this lens I'll need a teleconverter or something.

Link: http://www.amazon.com/Sigma-Angle-Telephoto-28-70mm-Compact-Autofocus/dp/B000H34T4I/sr=1-61/qid=1158261047/ref=sr_1_61/104-5717669-8926348?ie=UTF8&s=photo
 

iGary

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May 26, 2004
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HckySo said:
I wanted a cheap solution for a beginner wide-angle lens so I ended up ordering this $70 sigma lens yesterday. Today I just couldn't figure out why it was so cheap. It says somewhere in the details that it works with Digital cameras but in the title it only says "Nikon AF". I have a Nikon D50 and I'm wondering if when I get this lens I'll need a teleconverter or something.

Link: http://www.amazon.com/Sigma-Angle-Telephoto-28-70mm-Compact-Autofocus/dp/B000H34T4I/sr=1-61/qid=1158261047/ref=sr_1_61/104-5717669-8926348?ie=UTF8&s=photo
All Sigma's stuff says "For <insert manufacturer here> AF."

What would you need a teleconverter for?

*confused*

Looks like the right lense to me...

That price is kinda what they go for...
 

HckySo

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Apr 9, 2006
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I'm just worried because other ones say "for Nikon Digital AF" but this one only says "for Nikon AF"
 

iGary

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May 26, 2004
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HckySo said:
I'm just worried because other ones say "for Nikon Digital AF" but this one only says "for Nikon AF"
I'm no Nikon person, but I just looked at my Sigma 8mm and 12-24 and they both say "For Canon AF-" nothing about digital.

They work fine on the 20D and 1D MkII.

I'm sure you can return it otherwise, yeah?
 

bousozoku

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Jun 25, 2002
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HckySo said:
I'm just worried because other ones say "for Nikon Digital AF" but this one only says "for Nikon AF"
That just means that it's not optimised for Digital cameras. The Sigma DC series is Digital only and the DG work with 35mm and Digital.
 

timnosenzo

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Jun 21, 2004
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FWIW, that 28-70 isn't going to be very wide on your D50. With the crop it works out to about 42mm, which isn't really wide, its more a mid-range zoom.
 

Luca Mac

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Sep 14, 2006
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just reading the site:

Technical Details
From 28mm wide to 105mm tele range this zoom lens has 50cm (19.7inches) minimum focusing distance. It has also maximum magnification of 1:6.5.
Incorporates an Aspherical lens element to minimize distortion.
As part of the DG line, this lens is optimized for digital cameras.
The new multi layer lens coating and lens design reduce flare and ghost, which is a common problem with digital cameras and also creates an optimum color balance.
A zoom hood is supplied with this lens for complete depth in the telephoto range and glare-free shooting in the wide-angle range.
 

bousozoku

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Jun 25, 2002
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Luca Mac said:
just reading the site:

Technical Details
From 28mm wide to 105mm tele range this zoom lens has 50cm (19.7inches) minimum focusing distance. It has also maximum magnification of 1:6.5.
Incorporates an Aspherical lens element to minimize distortion.
As part of the DG line, this lens is optimized for digital cameras.
The new multi layer lens coating and lens design reduce flare and ghost, which is a common problem with digital cameras and also creates an optimum color balance.
A zoom hood is supplied with this lens for complete depth in the telephoto range and glare-free shooting in the wide-angle range.
Yes, it says that, but if it's optimised for digital cameras, then it must be bad for 35mm cameras. Besides that, why would they offer a digital-only line, if the DG line was optimal already? :D
 

andiwm2003

macrumors 601
Mar 29, 2004
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Luca Mac said:
just reading the site:

Technical Details
From 28mm wide to 105mm tele range this zoom lens has 50cm (19.7inches) minimum focusing distance. ......................................
your amazon link says : Sigma Zoom Wide Angle-Telephoto 28-70mm f/2.8-4 DG Compact High Speed Zoom Autofocus Lens for Nikon AF

not 28mm wide to 105mm. are you sure you looked up the right site?

anyway, lenses optimized for digital cameras give the image only for small (APS-C size) chips. they will not work for large chips and 35mm film. that's all the optimization there is.
the other lenses work for large chips and for 35mm film cameras and for APS-C cameras (with a crop factor).

the only problem is that you have to factor a crop factor in. that means multiply the lens numbers by 1.5 or 1.6. so you lens will be fine, it will work. but you get a picture eqivalent to a 42-105mm on film.

that is by no means wide angle. for a APS-C sized digital SLR you need something around 16mm or less to speak about wide angle (assuming you camera is APS-C size).
 

ChrisA

macrumors G4
Jan 5, 2006
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Redondo Beach, California
Not a really bad lens but not what you want

The lens will work fine on a D50 but 28mm is far from a "wide angle". It would be wide on a film camera but on a Nikon digital it will range from "normal" at 28mm to a mild telephoto at 70mm. (the digital sensor has a smaler frame size than a 35mm film frame.)

What lens do you have on the D50 now? In this price range the best lens would be the lens that is normally sold with the D50, the 18-55. 18mm is a wide angle

The full name of this lens is "Nikon 18-55mm f/3.5-5.6G ED AF-S DX"
 

Luca Mac

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Sep 14, 2006
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Milano
andiwm2003 said:
your amazon link says : Sigma Zoom Wide Angle-Telephoto 28-70mm f/2.8-4 DG Compact High Speed Zoom Autofocus Lens for Nikon AF

not 28mm wide to 105mm. are you sure you looked up the right site?


yes the site is right, but the technical description is wrong.
 

cube

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May 10, 2004
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bousozoku said:
Yes, it says that, but if it's optimised for digital cameras, then it must be bad for 35mm cameras. Besides that, why would they offer a digital-only line, if the DG line was optimal already? :D
The "digital optimization" of DG lenses might be good too for film cameras. They are not optimal for crop digital, as the DC lenses can be made smaller.
 

Mr_Ed

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Mar 10, 2004
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bousozoku said:
Yes, it says that, but if it's optimised for digital cameras, then it must be bad for 35mm cameras. Besides that, why would they offer a digital-only line, if the DG line was optimal already? :D
Not so. The post by andiwm2003 explains it all. The digital "optimization" relates to physical size of lens and focused image size, not optical quality. He is also correct about the digital "crop" causing a traditional 28mm focal length lens to behave like a 42mm in terms of coverage. If you are shooting only digital, traditional (for 35mm) lenses are overkill and digital optimized lenses are generally cheaper.

For a Nikon D50 (I have a D100, I believe it has similar sensor dimensions) I would say you want something in the 17-18mm range to actually have a field of coverage equivalent to 28-30mm range. It wasn't particularly cheap, but I bought a Tamron 17-35mm zoom last year and I'm very happy with it. I was previously shooting an F100 (35mm film) with a 28-105mm zoom and missed having that kind of relatively wide coverage. The 17mm was just about right for giving me back a "28mm" field of view.
 

cube

macrumors P6
May 10, 2004
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Sigma DG lenses are normal ones with glass improvements thinking about digital. I think they are also more telecentric.
Sigma DC lenses are digital-only because of their reduced size.