harvo

I have a D7100 and was looking @ a nikon 18-300 af dx. will the tamron or sigma equiv lens give the full frame use as with the nikon?

imagemeister Loc: mid east Florida

No 18-300 is full frame ...

rjaywallace Loc: Wisconsin

Sorry, harvo, but I don’t understand your question. Are you asking whether a Tamron or Sigma DX-equivalent lens is capable of capturing the same Field Of View as a Nikon DX lens?

amfoto1 Loc: San Jose, Calif. USA

I don't understand your question.

Are you thinking of changing from a D7100 DX camera to a full frame (FX) model and wanting lenses that will also accommodate the full frame camera?

Or are you asking it 18-300mm Tamron or Sigma lenses (which are DX designs, same as the Nikon lens) will give the same angle of view on your D7100?

Nikon full frame cameras allow DX lenses such as those to be used... HOWEVER, the camera will automatically crop the image to match the lens, and you will end up with greatly reduced resolution. For example, your D7100 is a 24MP camera. If you crop the images from a full frame, 24MP camera such as the Nikon D750, DX size images from it will only be about 10MP... almost 60% less resolution than you get now with your D7100.

So even though they will work in a limited way, it really doesn't make much sense to use DX lenses on an FX camera... Doing that basically defeats the whole purpose of buying the FX camera! FX cameras are best used with FX lenses.

gtick

I have both Tamaron and Nikon lenses. I bought my son the Tamaron 70-300 and I am thrilled with the results. I have Tamaron 60 prime and love it. For the price I am finding Tamaron well worth the price and produces incredibly sharp photos. With the price on Tamaron and all the reviews you cannot go wrong.

IDguy Loc: Idaho

Not quite. Automatic cropping to the DX image area is a user selectable option. A D800, for example, has five user selectable image areas from DX to FX.

Some DX lenses work fine with all five image areas, at least over part of the zoom range. Others will significantly vignette with some image areas larger than DX, again over some of the zoom range.

Nonetheless, if you get an FX camera it makes sense to get FX lenses when you can afford them. The 28-300 is the FX version of the 18-300.

ToBoldlyGo Loc: London U.K.

They would give a similar or identical field of view on a D7100, although no two designs will be identical even if the specs say they are. The D7100 is a 'crop' sensor camera, not a 'full frame' one, so the issue isn't relevant.

BebuLamar

Both Nikon and third party DX lenses are for the DX cameras and they are only guaranteed to cover the DX format. They may cover more but that is not part of their specs.

jamesl Loc: Pennsylvania

On your D7100 the brand wouldn't matter, an 18-300 lens will function as a 27-450mm lens due to the 1.5 crop factor in Nikon Dx cameras.