I would not do tamron. Better to go with the name brand. Tamron uses plastic lenses throughout. My wife is a photographer and has had to explain this to me before. I second shoot as she started teaching me years ago. I have a 50mm macro and on a camera with a crop sensor it gets way in there. If you are not shooting full frame and you get a lense that is made for it, the crop factor might be 1.6x the stated zoom. With an entry level camera as you say, I highly doubt it's full frame. I shoot canon so i don't know Nikon.
Long story short, a 50mm might be like shooting a 75mm on that camera and cheaper.
Sorry, but this is not good advise in THIS case.
I too am a photographer. I shoot commercially. A lot of food and product photography. I have years of experience with THIS EXACT lens and other macros like the Nikon 105vr.
The Tamron is optically 95% as good as the Nikon for 1/3 the price. For Nick's use, the Tamron is perfect. I used it professionally for YEARS. There is nothing wrong with a plastic body when the optics are this good.
I'm sure nick won't be beating on it on a regular basis, or shooting outside in inclement weather.
Of course the Nikon 105vr is awesome, but for the average user you can save a butt load of cash with the Tamron and see no difference in your pics which is what most people care about it.
As to full frame vs cropped sensor, that is an advantage in this case, with either lens.
Nick will get a longer reach, more like 120mm. Awesome for macro.
50mm is MUCH MUCH too short for macro, especially shooting our tanks where things like glass panels get in the way.
