What's my field of view on a 20mm f2.8D wide angle lens?

I apologize in advance for a stupid question, since I'm really illiterate when it comes to technical camera stuff. Since I don't have a full-frame camera with the D3100 so I'm assuming I don't get the best bang for the wide angle buck, but I could be wrong since it's not an FX lens.

Do I still get the full 20mm field of view or is there some cropping going on?

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Did you get the standard 18-55 kit lens with your D3100? If so you can see the field of view at 20mm. It will be the same with the 20mm f2.8D wide angle lens. It has the same as a 30mm on a 35mm camera

Thanks, yes I have a standard 18-55 kits lens, but that was from my D40. When I bought the D3100 about 6 months ago I got it with a fixed 35mm f1.8. I bought the 20mm because I was tired of having to walk backwards to get the shots I wanted.

Appreciate the reply.

Adrian MacNair said:

Thanks, yes I have a standard 18-55 kits lens, but that was from my D40. When I bought the D3100 about 6 months ago I got it with a fixed 35mm f1.8. I bought the 20mm because I was tired of having to walk backwards to get the shots I wanted.

Appreciate the reply.

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both of your cameras ar DX-format so the field of view is the same on both. The 18-35 should work on the D3100 just fine

Thanks, so it's only when I use an FX lens on my DX body that I would see cropping, right? Something like a factor of 1.6, so 14-24mm FX lens becomes a 22-38mm on a DX body.

I was just confused because the 20mm f2.8D is referred to as a wide-angle lens.

Adrian MacNair said:

Thanks, so it's only when I use an FX lens on my DX body that I would see cropping, right? Something like a factor of 1.6, so 14-24mm FX lens becomes a 22-38mm on a DX body.

I was just confused because the 20mm f2.8D is referred to as a wide-angle lens.

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You get cropping on all lenses. That is a factor of the camera. your 20 is like a 35mm on a full frame camera. Technically it is a wide angle lens BUT. You might as well use your 18-55 if you just want more wide angle. if you really want a wider field of view then you will need to go to a much wider lens like in the 10 to 15mm range.

Just put your 18-55 ket lens on and use it for a while to see how that works

Well, wide angle is nice, but it's not the only factor. I mean, there has to be some reason the 20mm is $500 more expensive than the cheapo model lol. Point of clarification: I only bought this lens last night. I've been using the 18-55 at the 18mm setting for all my shots, but if I have the space and room to back up for my shot, I prefer my 35mm f1.8 because the clarity of focus and depth of field is way, way better than the 18-55. I'm assuming similar results with the 20mm because the f2.8 gives a nice bokeh you can't really get with the 18-55 with a widest aperture of 3.5 at the 18mm mark.

Adrian MacNair said:

Well, wide angle is nice, but it's not the only factor. I mean, there has to be some reason the 20mm is $500 more expensive than the cheapo model lol. Point of clarification: I only bought this lens last night. I've been using the 18-55 at the 18mm setting for all my shots, but if I have the space and room to back up for my shot, I prefer my 35mm f1.8 because the clarity of focus and depth of field is way, way better than the 18-55. I'm assuming similar results with the 20mm because the f2.8 gives a nice bokeh you can't really get with the 18-55 with a widest aperture of 3.5 at the 18mm mark.

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That is correct. The quality of the 20mm and the 35mm is better and it is faster. The main thing you were talking about in the original post was the field of view though. Prime lens (fixed mm and not zooms) is generally better. A lot of what we are talking about is sharpness. What are you using the camera for, are you making very large prints. If not and you are only using it for posting on the web then most people will never know the difference. People here on the forum who are all into shooting probably will.

Would I want a 35mm lens and a 20mm lens? No. I would like the 35mm and probably a 14mm but that lens cost considerably more.

Haha, right you are about the price. The lens I really wanted is the Nikon AF-S FX 14-24mm f/2.8G IF-ED but it's $2,000. And also, it's an FX lens on a DX body. Alternately, the Nikon AF-S DX NIKKOR 10-24mm f/3.5-4.5G is $900.

I do photojournalism, and often my subjects are close to me so that's why I wanted a wide field of view, but it's certainly not the only reason. I like the 35mm a lot, but like I said, when you're shooting for a newspaper you're sometimes in these confined spaces where that lens doesn't cut it. The 18-55 works but the f3.5 starting point can be challenging for indoor lighting.

I do make large prints with my photos sometimes, but nothing larger than 5x8 for a magazine-style cover shot on our newspaper. Most of the photos inside the paper will be three or four inches at the most. That's part of the reason I got a D3100 because I don't need the extra megapixels.

Anyway, thanks for the chat. If I come into cash in the near future maybe I can get the 10-24mm lens. Any personal experience with that one?

A couple of points. If you are shooting indoors with existing light then shoot in RAW + Fine and you can color correct so much better using the RAW. I shot some downtown at night recently and the difference is amazing when you correct the RAW shots.

Yes, the 14-24 is an FX lens but, as others are pointing out, so is the 20 f/2.8D. Unless the lens is designated as DX it's FX. The 20 f/2.8D is one of the older FX designs but it is FX. I hope you weren't confused by the D in the model number as that stands for "Distance". The D lenses where the first to tell the camera at what distance the camera was focused. The D has nothing to do with DX. Also, you will not be able to use auto-focus with this lens or your D3100 as your camera does not have a focus motor and neither does this lens. For autofocus on the D3100 you need AF-S lenses. One last point, I've heard from reliable sources that certain lenses, and this is one, actually perform better on FX bodies than DX bodies. That's opposite of what you'd expect.

Thanks, jwstl. yes, I noticed you can't autofocus since you need a focus motor like on a D300. But there's a decent hack to it. The 13 focal points on the viewfinder still measure distance, so while I'm manually focussing with the lens the focal point if I hold the shutter halfway down then the circle will go solid green when I'm sharp.

Adrian MacNair said:

Thanks, jwstl. yes, I noticed you can't autofocus since you need a focus motor like on a D300. But there's a decent hack to it. The 13 focal points on the viewfinder still measure distance, so while I'm manually focussing with the lens the focal point if I hold the shutter halfway down then the circle will go solid green when I'm sharp.

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That's correct. I have a number of manual focus lenses I use on my digital bodies and the focus indicator works well. If you are on a tripod and can use Live View, even better.

Tracsoft - Don Kuykendall said:

You get cropping on all lenses. That is a factor of the camera. your 20 is like a 35mm on a full frame camera....

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Um ... unless things are different with Nikon - the reason Dx Lenses aren't desirable on Fx bodies is because Dx lenses won't cover the sensor. So on a Dx frame they cover the entire sensor with no overlap or 'crop' in the projected image, other than that necessary to fit a round image onto a rectangular sensor - lol, unlike Fx lenses which has a cropped projection on a Dx sensor because it is designed to fit a Fx sensor. Yes - by default you have a smaller 'crop' sensor - but OP was referring to projected image I think. Can you clarify because now I'm confused lol.

**Edit - OP, welcome to the forum

Here's the answer if anyone cares. Camera Lens Explained | DX & FX Format Lenses from Nikon from Nikon

The difference in size from Dx to Fx = 1.5x so a 20mm lens would be 30mm equivalent on a Dx sensor.

Get the 10-20m sigma if is wide you want ...

Thanks for all the replies. Forgive my brutal ignorance but what Nikon brand would show the full frame of an FX lens? A D300?

Also, is there an article I can read that would help me better understand?

Never mind, I found a list of full frame Nikon bodies:

Nikon D600 13 September 2012
Nikon D800 07 February 2012
Nikon D800E 07 February 2012
Nikon D4 06 January 2012
Nikon D3S 14 October 2009
Nikon D3X 01 December 2008
Nikon D700 2008 July 01
Nikon D3 2007 August

Sorry again for the dumb question