I'm getting a new glass!!! Nikkor 50 mm 1.8 f prime for Mother's Day ..

[Horoscope Fish]

I may never be able to keep this straight -- I'm confused everybody. If Tammy is shooting with a D5100, wouldn't a DX-format lens be a better match? I ask because I may seek a prime lens someday, but probably a 35mm to replicate the as-I-see-it 50mm view I had with my film SLR. Thanks for clearing up my confusion.

You can put an FX lens on a DX body no problem. The reason is because the image cast by the FX lens is larger than the DX sensor. This being the case, the camera sensor will be using the center-most portion of the larger field of view cast by the FX lens which is where you get the best resolution; the center is the "sweet spot".

Conversely, if you were to put a DX lens on an FX body, the image projected by the lens would be smaller than the sensor the image is falling on, so then your shots wind up with dark corners, an effect called vignetting.

Let's use an illustration to illustrate this...

See how the DX sensor area falls squarely in the center of the FX image circle? That's the "sweet spot" I'm referring to. You can also see how putting the DX lens on an FX body would "crop" the image giving the dark corners (red/white circle vs big blue sensor area).

Hope that helps to clarify things.

...

 

[Sandpatch]

Okay, I think I see it now - thank you! I guess the other bonus buying FX lenses would be that if a future upgrade to an FX body was made, the owner wouldn't have a collection of DX lenses to unload. I'm guessing that FX lenses cost more then DX, but haven't shopped and don't really know.

 

[Horoscope Fish]

... I guess the other bonus buying FX lenses would be that if a future upgrade to an FX body was made, the owner wouldn't have a collection of DX lenses to unload. I'm guessing that FX lenses cost more then DX, but haven't shopped and don't really know.

Correct on both counts.

 

[TammyL.Campbell]

It's good to know..thanks for the tutorial.Horoscope Fish

 

[TammyL.Campbell]

I've got my lens now..so happy!!! I snapped pictures like crazy today too.lucked out and came a crossed a salt marsh moth for my macro work.. It's been awesome so far.. Will post photos soon.