compatable lenses for Nikon D3100

[thegrump]

A friend offered me a Sigma 70-300mm F4-5.6 DG MACRO, if it fit. I googled "compatible sigma lenses for Nikon D3100" and I came up with this exact lens. I now have this lens but it does not quite fit. Does Sigma make this lens to suit various cameras? or can you change the fixture on the lens to suit my camera? or do I put it on eBay? The lens is brand new and in the box, it does have FOR PENTAX AF on the box.

[John King]

Gidday TG

Sigma, Tamron, Tokina and others make lenses that are all but identical for a number of different lens mounts and communication protocols (the electrical connectors on bodies and lenses). Almost always both the mount and electrical connections are brand specific, so off to FleaBay (or here ... ), unfortunately :(.

How's your knee progressing?

[ameerat42]

I have that lens for my Σ. It's not too bad. I no longer use it much
because the 50-500 has supplanted it.

But that's just BTW as to its quality. Your MAJOR (you can salute here) PROBLEM
is that it's for the WRONG camera:(:( You need the NIKON mount on that lens.

From what I know, they're not too expensive (and I hope that was the case for you).
As John said, sell it - IF you can't send it back for a refund.

[arthurking83]

..... The lens is brand new and in the box, it does have FOR PENTAX AF on the box.

Easy answer: NO!!!

Interesting answer: yes-ishhhhh! But there's a lot of stuffing about and possible damage done to either device.(hence why the Easy answer of No! ;))

Pentax K mount lenses can be fitted to Nikon F mount cameras, with a lot of care. It's not the same mount, but the notches in the bayonet can be 'squeezed' to fit. The lens won't lock into place .. so there is a very high probability that the lens may fall off!!(hopefully I've scared you off at this point, as it only gets worse from here :p)
The Pentax mount is shorter than the Nikon mount, so there MAY be a situation where the rear of the lens may be deep enough inside the mirror box that the mirror hits the lens with a catastrophic sound of smashing mirror parts bouncing off all the sensitive internal areas!!
If that didn't care you off, then not much will :D
Oh! and if you do try it after all of that, make sure that the lens is an earlier model with an aperture control ring .. otherwise all you get is a black viewfinder and or Liveview image.
Surely!!!! ... at this point you have no desire to try this out for yourself.

FWIW: this is one of those cheapy lenses that I actually liked for the most part.
It's not the greatest lens ever made, but it punches above its weight considering it's price point.

Note that if you'd like to try this lens in a Nikon mount .. it HAS to be a HSM version(later/newer), and not the screw driven type(earlier versions) if you want AF.
These lenses are pretty cheap brand new, so second hand you should be able to find one very very cheap.
New at about $150-200 for the older type, and about mid $300's for the newer model with OS(which is the one to go for).

Also note: the macro feature is only available at 300mm and this lens is not very good at 300mm at any focus distance. It will give you reasonable images but not very sharp.
Up to about 250mm the lens is quite usable in terms of IQ.
So don't expect sharp macro images from one.

[thegrump]

eBay it is...............................

[ameerat42]

Hmm! I might haffter get it back out and check this theory, AK. I thought it was "rather OK" at 300mm,
and only showed a bit of CA at the shorter FLs...
...
When I find it again.

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Certainly that mount isn't of much use to you, TG.

[arthurking83]

Hmm! I might haffter get it back out and check this theory, AK. I thought it was "rather OK" at 300mm,
and only showed a bit of CA at the shorter FLs...
.....

It's usable as long as you don't expect the image to to cut your eyes open like a razor can! :p

The best adjective I can use to describe the resultant image is usable over the entire frame and at selected reproduction ratios ... (and don't crop or don't crop too heavily)

I used to have(access to) the older version of this lens(screw driven type) and liked it a lot.

A few years back I also played with one again and remembered how good it is(for the money!) .. had weird thoughts of getting one again just for the fun of it.

TG!! if you do search ebay, just be sure that if you do bid for one .. and you want autofocus ability .. it needs to have either a built in AF motor(it'll say so in the description) or HSM(Sigma's version of AF-S lenses).
Note that they will all mount to a Nikon camera if it's a Nikon mount, with aperture control and metering and so on ... it's just the AF issue that you want to watch out for.

[ameerat42]

In a little while I will post some pics I just took.
But the WONDER of it all is that I FOUND the lens:nod:

Over a year of non-use it zipped back and forth in AF like...

- - - Updated - - -

Prelim findings:
I need to use a tripod or something as I cannot hold it steady without OS.
Need to take more shots:(

- - - Updated - - -

Conclusion:
I won't break my neck to get tripod shots.
TG, they came with AF no problem, but I can't remember if there were any with
optical stabilisation. Without that, I have found it impractical to use in macro.