FX lens on DX body

[hamlet]

I have a question pertaining to the FX lenses on the DX bodies. If i were to get a 50mm 1.4g from nikon, that would be an equivalent to a 75mm on my DX camera. Would this lens choice make the 85mm a meaningless purchase? The 50mm 1.4g (75mm on dx body) coupled with the 35mm 1.8g would make a very good combo. Am i wrong about this?

 

[robbins.photo]

I have a question pertaining to the FX lenses on the DX bodies.

Don't do it. Your children will be born sterile.

If i were to get a 50mm 1.4g from nikon, that would be an equivalent to a 75mm on my DX camera. Would this lens choice make the 85mm a meaningless purchase? The 50mm 1.4g (75mm on dx body) coupled with the 35mm 1.8g would make a very good combo. Am i wrong about this?

Well, not quite actually. A 50 mm 1.4g lens on a Nikon with a crop factor of 1.5 will give you the same perspective as a 75 mm lens, it does not however truly change the focal length of the lens itself. Might be splitting hairs a bit but there is actually a difference. If you were to go with an 85 mm of course that would give you the same perspective as if the focal length were roughly 130 mm. So really it will just depend on what sort of focal lengths you think you'll need.

 

[480sparky]

No. An 85mm on a DX body will have the same FOV as a 128mm on an FX.

Please don't use 'an equivalant' when using the crop factor. A 50mm lens on a DX body is still 50mm. The biggest difference is FOV. It's not magically a 75mm. It's 50mm, 24/365. Get an adapter to put it on a Nikon J camera and it's still 50mm.

 

[tirediron]

It really depends on what you want / need. The 35/50/85 (50/75/135 FOV equiv) is a very good combination, and until the advent of the decent quality zooms in the mid 80s, the standard trifecta was 28, 50 and 135.

 

[Juga]

Kinda but not really. 35mm = 35mm and 50mm = 50mm. The thing with crop sensors are that they 'cut' off the edges of what a full frame would display. The advantage however is that the pixels are more saturated than what the full frame would give you. So with a 50mm on a crop sensor you would have to give yourself more room to capture what a full frame would give you with a 50mm.

 

[Tinderbox (UK)]

A FX lens on an DX body, I have heard people mention the sweet spot of the lens, the center has least distortion?

John.

 

[480sparky]

A FX lens on an DX body, I have heard people mention the sweet spot of the lens, the center has least distortion?

John.

Less optical flaws, such as chromatic abberation, barreling/pincushioning, etc.

 

[Derrel]

On APS-C or "DX" as Nikon calls it, the 50mm prime becomes a fast-aperture, sharp, light, economical short telephoto lens. Nikon's 50mm f/1.8 AF-S G has aspherical element design, and is affordable, sharp, and a great value. If the camera in use were a traditional 35mm film SLR, the angle of view the 50mm lens would be thought of as roughly a 75mm short telephoto, like Leica used to make decades ago.

Nikon's 85mm f/1.8 AF-S G used on a DX Nikon body becomes a medium telephoto of roughly 127.5mm "equivalent angle of view" in terms of a traditional 35mm or "full-frame" or FX digital camera. The 85mm 1.8 G series offers almost unheard of optical quality for a lens under $1700 in price, and it has pleasing bokeh. In simple terms, using an 85mm lens on a Nikon DX camera is similar to using a 135mm lens on an older 35mm camera, only with a slightly wider angle of view.

 

[amolitor]

I use a 50 on my D3100 all the time. It's a very nice length, it doesn't feel "telephoto" really, but it does tend to isolate things pretty well. It feels like a regular lens, but kind of up-close and personal.

 

[robbins.photo]

A FX lens on an DX body, I have heard people mention the sweet spot of the lens, the center has least distortion?

John.

Very true. However, still there is that sterile kids issue. So, tossup really. Lol

 

[hamlet]

I have a question pertaining to the FX lenses on the DX bodies.

Don't do it. Your children will be born sterile.

If i were to get a 50mm 1.4g from nikon, that would be an equivalent to a 75mm on my DX camera. Would this lens choice make the 85mm a meaningless purchase? The 50mm 1.4g (75mm on dx body) coupled with the 35mm 1.8g would make a very good combo. Am i wrong about this?

Well, not quite actually. A 50 mm 1.4g lens on a Nikon with a crop factor of 1.5 will give you the same perspective as a 75 mm lens, it does not however truly change the focal length of the lens itself. Might be splitting hairs a bit but there is actually a difference. If you were to go with an 85 mm of course that would give you the same perspective as if the focal length were roughly 130 mm. So really it will just depend on what sort of focal lengths you think you'll need.

So its not really the same is what you're saying? Its not making any sense to me.

 

[hamlet]

On APS-C or "DX" as Nikon calls it, the 50mm prime becomes a fast-aperture, sharp, light, economical short telephoto lens. Nikon's 50mm f/1.8 AF-S G has aspherical element design, and is affordable, sharp, and a great value. If the camera in use were a traditional 35mm film SLR, the angle of view the 50mm lens would be thought of as roughly a 75mm short telephoto, like Leica used to make decades ago.

Nikon's 85mm f/1.8 AF-S G used on a DX Nikon body becomes a medium telephoto of roughly 127.5mm "equivalent angle of view" in terms of a traditional 35mm or "full-frame" or FX digital camera. The 85mm 1.8 G series offers almost unheard of optical quality for a lens under $1700 in price, and it has pleasing bokeh. In simple terms, using an 85mm lens on a Nikon DX camera is similar to using a 135mm lens on an older 35mm camera, only with a slightly wider angle of view.

This isn't helping either.

 

[Derrel]

I use a 50 on my D3100 all the time. It's a very nice length, it doesn't feel "telephoto" really, but it does tend to isolate things pretty well. It feels like a regular lens, but kind of up-close and personal.

I think this is interesting, and amusing, all at the same time. But it does have a certain very real basis in truth to it; if a fellow uses a lens all the time, it tends to begin to feel "regular". And honestly, a 50mm lens is not "exotic" in the sense that a 16mm fishey is exotic, or a 300mm f/2.8 or 400/2.8 is an "exotic" lens.

One of the nice things about a 50mm lens as a short telephoto is that the smaller capture size of APS-C means that there is MORE depth of field at the angle of view a 50 gives on the smaller APS-C size frame than there is with the same angle of view on an FX body. That's one part of the reason that amolitor can easily use a 50mm on his D3100; the size of the camera's capture format gives pretty good depth of field; enough so that in the real world, a 50mm lens is an easy-to-use lens for a lot of picture taking situations. I think that the somewhat increased depth of field that a DX-sized sensor has makes it much easier to get enough DOF to actually make "good pictures" of people, and things, and places. I know a lot of people get all happy-happy about shooting wide-open and having like 2 inches in focus, but I would rather be at f/4.5 and get a foot or two or three feet in focus, and be able to make pictures with a bit of freedom.

 

[Derrel]

This isn't helping either.

While I was writing the above post, you posted this. I'm sorry. I'm not sure what I can provide in order to be more helpful.

On a DX NIkon a 50mm lens is a very short telephoto lens. It is not a long tele, and not a medium tele, but a VERY SHORT tele. It has what I would call a "somewhat selective" angle of view. It helps you pick out small segments of a scene from 10,15,20,30 feet away.

On a DX Nikon, their 85mm 1.8 G lens is a MEDIUM-length telephoto lens, which a much more narrow angle of view than the 50mm offers. It is long enough that it creates some of what is commonly called "telephoto compression", meaning it magnifies the actual SIZE of images, both in the foreground, and also objects that are in the distance. It literally MAGNIFIES THE SIZE of things that are in the background!!!! This effect tends to make distances appear closer, and tends to make objects appear "stacked up" or "compressed into less space".

 

[JTPhotography]

An easy way to think of it is if you take the exact same shot (camera located in the same position for both shots) with the same lens on a full frame body and a crop body, the only difference would be that there would be less of the image showing up on the photo taken with the crop camera. It would be cropped. That's easy enough.

If you try to replicate two identical photos with a full frame and a crop camera by using two different lenses, say a 50mm on the crop and an 85mm on the full frame (those two dont exactly equal the crop factor but it is close enough for my example), then you would have to move the position of the cameras, and thus you would move the camera in relation to the background objects, and this would result in a different looking photo. The depth of field would be different.

There will also be a slight persective difference, maybe a bit more distortion with the wider one. This would be of most concern if you were shooting faces and head shots.

The differences may not be much, and it may matter to some people more than others.

I think what you essentially want to know is whether it is ok to substitue one focal length on crop. In other words, if an 85mm is a common portrait lens for full frame users, would a 50 serve the same purpose. The answer is, pretty much, but not totally.