Sigma 10-20mm D DC

Helium_Junkie

Helium_Junkie

Helium_Junkie

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Can someone explain further the meaning of D and DC on this lens? The sigma site says this for DC:

"These are special lenses designed so that the image circle matches the smaller size of the image sensor of most digital SLR cameras. Their specialized design gives these lenses the ideal properties for digital cameras, the compact and lightweight construction is an added bonus!"

Does this mean that it's a true 10mm? the that 1.6 crop factor thing doesn't actually apply?

And the single D on its own, is that the glass grade? And if so, is D good? Both of my Nikon lens' are G, is G worse?
 
Although the lens only works on 1.6 crop cameras they quote the actual focal length of the lens which is 10mm. To work out the equivalent 35mm field of view you need to apply to 1.6 crop factor.

Thus, it gives an equivalent 35mm focal length of 16mm.
 
Helium_Junkie said:
So the DC thing - what does it actually mean?
Click to expand...

I think its just Sigma's code for lenses that have been designed especially for digital SLRs with cropped sensors, and so shouldn't be used on film SLRs.
 
DC just means the image circle produced is smaller to match the small size of the APS-C sensor and as such you can't put it on a FF camera or it will vignette.

No idea about the D really, but i doubt it has anything to do with the NIkkor G label, you can't really compare labels across brands.


edit - actually I think the D might denote that it's Nikon fitment not Canon, I don't know if the Canon model has the D in it's name.
 
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The 'D' on its own doesnt actually form part of Sigma's own description of the lens, so I'm not sure if it means anything.
 
Joe T said:
The 'D' on its own doesnt actually form part of Sigma's own description of the lens, so I'm not sure if it means anything.
Click to expand...


It is written on the lens though, which is what leads me to think maybe it denotes Nikon fitment.

Also Sigma have this at the bottom of the page about the lens...

Corresponding AF Mounts

SIGMA,
CANON,
NIKON (D),
SONY/MINOLTA,
PENTAX
 
Joe T said:
^^^ good point. So does that mean its something to do with having an aperture ring?
Click to expand...

Well, mine doesn't have a ring like my 70-300 does, but it might still require something different for Nikon mounts
 
Found this about the nikon d series lenses.

Nikon's D-series SLRs all share a 1.5x focal multiplier (similar to most other SLRs) - which means that since the camera's sensor is smaller than a 35mm film frame, the field of view of a digital SLR image is a smaller crop of the view you'd get with the same lens on a 35mm film camera. This focal length multiplier has made it difficult for digital SLR owners to get truly wide-angle images from their lenses - but with lenses designed specifically for these smaller sensors, DSLR owners can look forward to taking up wide-angle photography once more.
Click to expand...
 
"but with lenses designed specifically for these smaller sensors, DSLR owners can look forward to taking up wide-angle photography once more."


That again sounds like it's implying that the lens is made to adjust for that 1.5x crop factor and still provide true 10mm goodness.
Oh I dunno. Would love to see comparitive shots of this lens and a 35m equivalent.

Also, what's the aperture ring all about?
 
It sounds like that, but it won't provide true 10mm, as can be seen by the fact a 12mm lens on FF is far wider than 10mm on APS-C.

Aperture Ring is found on non G type lenses, though i've never seen any use for it and have no idea what the point of it is because if you set it to anything other than the highest value the camera wont work. The 10-20 doesn't have an aperture ring anyway.
 
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