Djedi

My brother-in-law has the Nikkor 200-500mm. I own the Sigma Contemporary 150-600mm. Maybe he has a poor sample and I have an exceptionally good Sigma, but my copy had the edge in both sharpness and stabilization. The only thing I liked about the Nikkor is the build quality, but I don't think it would be as convenient to take into the field for hours at a time.

dcampbell52 Loc: Clearwater Fl

Actually, a 300mm FX lens and a 300mm DX lens will display EXACTLY the same. 300mm is 300mm. Yes both will crop giving the same appearance of a 450mm lens on an FX camera. The main issue on DX is if you are trying to go wide angle. I have a 10-24mm DX lens. It gives a similar image to a 15-36mm lens on an FX camera so wide angle on DX is MORE difficult. to really get the wide angle effect of a 10mm FX lens you would have to purchase a 6.4mm lens which would roughly give you 10mm. (This is one of my main reasons for having both a DX and FX camera, I just use my wide angle lenses on my FX and my longer lenses on the DX as needed). Note: a 50mm lens on a DX would be similar to a 75mm lens. But all lenses are listed (both DX and FX) with their regular millimeter length. In other words the 300mm lens is a 300mm whether FX or DX it just looks similar to a 450mm on the DX. There are a few other differences such as depth of field etc. Personally, I would just keep the wide angle issues in mind and try to purchase FX only lenses so that you can easily go back and forth.

mikeroetex Loc: Lafayette, LA

I mix and match... my longer lenses for action shots are FX. But I get great results with 17-50 for DX and 11-16mm DX for everything else. It's really about your budget and where you intend to wind up. I think at some point I'll have a kit of both ranges, especially with the D750 dropping in price!

repleo Loc: Boston

" I was thinking that maybe I should buy an FX lens for my next lens purchase in case I ever decide to get a FX body."

One of the main differences between a so-so lens and a premium lens is how well it handles the edges and corners. If you put an FX lens on a DX body you will be using the sweetest part of the lens and cropping out the troublesome edges and corners. So if you pay the extra for a premium FX lens you are not really taking advantage of it premium capabilities on a DX body. However, if you ever move up to a FX body, will you be happy with so-so FX lenses.
I think the best thing is to make up your mind and get off the fence. If you aren't convinced by the smaller size, weight and cost of DX and really see the need for an FX camera in the near future, do it now, get it out of your system and buy the best lenses you can for it. Don't think too far down the road. In five years time, we may all be using camera phones or medium format cameras.

jeep_daddy Loc: Prescott AZ

There is a brand new Tamron 150-600 G2. or Generation 2. A friend of mine just bought it and loves it. He has the older or first generation and did some comparing and says that the new G2 lens is much sharper than his older lens. Personally, I like to use lenses made by the company that makes the camera. If it's a Canon, buy Canon lenses. Nikon, buy Nikon.

I have Canon equipment. I started with my first lens as a DX lens. (Canon doesn't call it that they call it the EF-s series of lens) All the EF-s lenses are for the DX or APS-C crop sensor bodies. But the APS-C crops sensor bodies will accept all of Canon's lenses including the best of the best. I decided after buying that first DX lens that it doesn't make sense to keep buying those in case I want to upgrade the body some day to a FX or Full Frame body. I'm glad I went this route because now I have one of each. A full frame body and a APS-C body and all my lenses can be shared and work wonderfully.

amfoto1 Loc: San Jose, Calif. USA

Isn't the extra size, weight and cost enough reason?

Especially considering that if/when you ever actually do decide to get an FX camera, you can pretty easily sell off or trade in any DX lenses and switch to FX lenses then.

OTOH, with APS-C DX cameras getting better and better every year, getting the bulk of the R&D attention, maybe you'll never "need" FX at all. Lots of people who use FX cameras don't actually get any or very much benefit from them. They end up resizing the images down for online display or to make common size prints, so no one else ever sees any difference.

Well, other considerations.... FX lenses typically don't get into focal lengths that will be truly wide on DX cameras. The widest Nikkor FX lens is 14mm (other than fisheye lenses with heavy distortions). That's significantly less wide than a 10mm lens. At the wide end of things, 1 or 2mm makes a whole lotta difference.

Also, a 14-24mm FX lens has a convex front element that prevents attaching a standard filter, while a 10-24mm DX lens doesn't and can use standard 77mm filter. (Not to mention that the 14-24mm is $1000 more expensive and more than twice as heavy.)

HOWEVER, you're asking about telephotos and, specifically, the Tamron 150-600mm. Like all telephotos reaching 400mm or longer, those are both FX lenses anyway. The difference in price you're seeing is merely the older model that's recently been discontinued and is being cleared out with hefty discounts, versus the new and improved "G2" model, as Tamron calls it.

jackpi Loc: Southwest Ohio

Both of the Tamron 150-600mm lenses are FX lenses. The G2 version is a more advanced design that is sharper at 600mm and provides added features that are of value to some photographers. There is no equivalent DX telephoto zoom lens.

In general, FX lenses cost more and are heavier but provide no significant improvement in image quality on a DX camera.

dcampbell52 Loc: Clearwater Fl

Yes and a DX 10mm is virtually the same as an FX 14mm so what's your point? The IQ of a (key word here) good FX lens, while heavier and more expensive, is going to have a better build, you will be shooting at the "sweet spot" of the glass, it is going to be compatible with both DX and FX cameras so your upgrade ability is guaranteed. (Why buy a collection of DX lenses and then try to get rid of them (at a loss) when you can get higher quality (not kit) FX lenses and be done with your purchase. Sure, you can get some okay DX lenses but any quality or professional lenses will be FX (even prosumer lenses will be FX). at least in Nikon. You might be able to get some good Sigma or other brands (not Tamron) with out going to FX but Nikon's DX lenses tend to be "entry level" lenses.

OddJobber Loc: Portland, OR

Party pooper.

mborn Loc: Massachusetts

In the beginning, when there was only DX digital camera it did not matter now I buy FX Lenses and use them on either a DX or an FX body

NikonCharlie Loc: Kansas USA

Your comment: While 24mm will be very useful with a full frame camera for wide angle shots with your DX body it will only be 36mm.
DX lens is exactly that way also, all DX lenses have the .5X factor.

BebuLamar

Nikon doesn't make a 24mm lens for the DX format but if they do it's only a wide angle while the FX lens is classified as ultra wide angle as it can cover 84 degrees angle of view when mounted on an FX camera. The 24mm lens DX (if available) can only cover 63 degrees or so no matter which camera you mount it on.

dcampbell52 Loc: Clearwater Fl

Actually, while Nikon doesn't make a 24mm DX lens for DX, they do make a 10-24mm zoom DX lens. And yes, it does "suffer" from the .5 angle of view problem which makes it similar in angle of view to a 15-36mm FX zoom. This is the reason that I tend to put FX lenses on FX cameras for my wide angle to 50mm shots and then either put a 50mm FX lens on my DX or use the longer FX (or DX) lenses on my DX to take advantage of the crop.

NikonCharlie Loc: Kansas USA

While 24mm will be very useful with a full frame camera for wide angle shots with your DX body it will only be 36mm.

I used the 24mm example by quoting the reply. I recall 35mm fixed in DX, maybe. I don't use DX lenses.

cjc2 Loc: Hellertown PA

Buying FX lenses is like planning for the future -- IF you go FX, you will have some lenses for it. Both the Tamron lenses you mention are FX format. I would suggest considering the Nikon 200-500 if you are considering the more expensive version. Best of luck. Happy Holidays!