silly question...

dukeboy1977

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I always see that 50mm is not good for portraiture, BUT I shoot on a DX Nikon D3100 which has a crop factor of 1.5x, so 50mm is really like 75mm. Am I to understand that on MY body, since it's NOT FX, the AF 50mm 1.8D is actually a good starting point? I understand that a good length is between 50-100mm so 75mm is about perfect then, right? I've been looking and looking for a good lens for portraiture since seeing that a while ago, and this dawns on me at work today! DUH!! lol On my body the 50mm 1.8D should be a decent lens for portraiture, right? Not optimum because of the flat aperture blades, but better than the basic lenses. Am I understanding this right? My 35mm AF-S 1.8 is really about 50mm on my body so that is kind of a decent start too? Is this 50mm 'rule' going by FX standards?
 
A 50 mm lens (DX lens or FX lens) on your DX camera is really like a 50 mm lens on your camera.

However, it delivers approximately the same field-of-view a 75 mm camera would if the 75 mm lens was mounted on a camera that had a full frame (FX), non-crop, image sensor.

Oh, and your thread was moved out of the Beginner's forum - http://www.thephotoforum.com/forum/...-forum/257684-notice-use-beginners-forum.html
 
A 50 is your best bet for protraits on a DX... especially indoors. A 35mm has too much distortion... and can make faces look really funny! A 85 is great outdoors... but way too tight indoors.

As Keith mentioned.. a 50 is still a 50... just your FOV is cropped.
 
Err, no lens actually "distorts" anything, unless it is designed to (fisheye) or imperfect (such as having a pincushion distortion).

The issue with distortion in portraits is that people usually look best about 5m away. At this distance, with a wide lens, you will get a lot of environment that you dont want in the shot. But peoples faces wont be distorted at all, despite the wide lens, unless the lens is imperfect.

Distortion happends if you photograph people much closer, or much more far away, than the ideal distance of about 5m.

But this rule with 5m isnt very strict. You can get quite a bit closer or more far away without much effect. In fact some faces might even look better if you are a bit closer or more far away.

Furthermore, people love to use prime lenses for portrait, because prime lenses can have higher (i.e. actually smaller) f-numbers, thus allowing a smaller depth of field and making it easier to put the background of the portrait out of focus. However, this is perfectionism - if you have some control of the shot, just avoid portraits on backgrounds that are too close.

A really important issue there is bokeh. Bokeh describes how the camera behaves in the out of focus areas. Its useless to have the background out of focus if the lens has bad bokeh and is thus both unsharp and dominant. Thus I would say this detail is actually the most important about thing about a good portrait lens. Fortunately lenses with bad bokeh are quite rare today, anyway.

People here at this site claim the 35mm F/1.8 DX has not that great bokeh, so it would be a suboptimal choice for a portrait lens.

See also:
Bokeh - Wikipedia, the free encyclopedia
Portrait Lenses
 
Err, no lens actually "distorts" anything, unless it is designed to (fisheye) or imperfect (such as having a pincushion distortion).

The issue with distortion in portraits is that people usually look best about 5m away. At this distance, with a wide lens, you will get a lot of environment that you dont want in the shot. But peoples faces wont be distorted at all, despite the wide lens, unless the lens is imperfect.

Distortion happends if you photograph people much closer, or much more far away, than the ideal distance of about 5m.

But this rule with 5m isnt very strict. You can get quite a bit closer or more far away without much effect. In fact some faces might even look better if you are a bit closer or more far away.

Furthermore, people love to use prime lenses for portrait, because prime lenses can have higher (i.e. actually smaller) f-numbers, thus allowing a smaller depth of field and making it easier to put the background of the portrait out of focus. However, this is perfectionism - if you have some control of the shot, just avoid portraits on backgrounds that are too close.

A really important issue there is bokeh. Bokeh describes how the camera behaves in the out of focus areas. Its useless to have the background out of focus if the lens has bad bokeh and is thus both unsharp and dominant. Thus I would say this detail is actually the most important about thing about a good portrait lens. Fortunately lenses with bad bokeh are quite rare today, anyway.

People here at this site claim the 35mm F/1.8 DX has not that great bokeh, so it would be a suboptimal choice for a portrait lens.

See also:
Bokeh - Wikipedia, the free encyclopedia
Portrait Lenses

i see what you are trying to say but i think you are confused between perspective and distortion. that 10mm will infact distort, if u place your subject in the middle there will be barrel distortion unless it is a perfect lens. If you try to fill the frame with a 10 to get the same image as you would with a 50, you mess up your perspective to the point where their face "looks Distorted, ie. nose is massive" Distortion is sometimes easy to fix in post but when you smudge pixels around you loose some sharpness and you also loose the edges of the frame. Perspective however is impossible to fix in post.
 
Err, no lens actually "distorts" anything, unless it is designed to (fisheye) or imperfect (such as having a pincushion distortion).<br>
<br>
The issue with distortion in portraits is that people usually look best about 5m away. At this distance, with a wide lens, you will get a lot of environment that you dont want in the shot. But peoples faces wont be distorted at all, despite the wide lens, unless the lens is imperfect.<br>
<br>
Distortion happends if you photograph people much closer, or much more far away, than the ideal distance of about 5m.<br>
<br>
But this rule with 5m isnt very strict. You can get quite a bit closer or more far away without much effect. In fact some faces might even look better if you are a bit closer or more far away.<br>
<br>
Furthermore, people love to use prime lenses for portrait, because prime lenses can have higher (i.e. actually smaller) f-numbers, thus allowing a smaller depth of field and making it easier to put the background of the portrait out of focus. However, this is perfectionism - if you have some control of the shot, just avoid portraits on backgrounds that are too close.<br>
<br>
A really important issue there is bokeh. Bokeh describes how the camera behaves in the out of focus areas. Its useless to have the background out of focus if the lens has bad bokeh and is thus both unsharp and dominant. Thus I would say this detail is actually the most important about thing about a good portrait lens. Fortunately lenses with bad bokeh are quite rare today, anyway.<br>
<br>
People here at this site claim the 35mm F/1.8 DX has not that great bokeh, so it would be a suboptimal choice for a portrait lens.<br>
<br>
See also:<br>
<a href="http://en.wikipedia.org/wiki/Bokeh" target="_blank">Bokeh - Wikipedia, the free encyclopedia</a><br>
<a href="http://www.kenrockwell.com/tech/portrait-lenses.htm" target="_blank">Portrait Lenses</a>
<br><br>

i see what you are trying to say but i think you are confused between perspective and distortion. that 10mm will infact distort, if u place your subject in the middle there will be barrel distortion unless it is a perfect lens. If you try to fill the frame with a 10 to get the same image as you would with a 50, you mess up your perspective to the point where their face "looks Distorted, ie. nose is massive" Distortion is sometimes easy to fix in post but when you smudge pixels around you loose some sharpness and you also loose the edges of the frame. Perspective however is impossible to fix in post.

the 35 is not bad at portraits you just have to incorporate more of the environment, also i found it shot better at 2.8 than it did at 1.8 not sure why the bokeh seemed more rounded and didn't have an extra circle in a circle effect going on. Good lens on DX. I actually shot a few portraits with a 10-20 at 20mm and i found it to be awesome, but remember unless you want your girlfriend to flip out cause her nose looks massive, move away from her and incorporate the rest of the environment with a wide lens.
 
A 50 mm lens (DX lens or FX lens) on your DX camera is really like a 50 mm lens on your camera.

However, it delivers approximately the same field-of-view a 75 mm camera would if the 75 mm lens was mounted on a camera that had a full frame (FX), non-crop, image sensor.

I'm not sure I understand the subtle difference you are trying to make here. Can you please flush out the difference between a 50mm on a DX body with a 75mm FOV, versus a 75mm lens on an FX body. Isn't it the same difference?
 
35mm Is considered a wider than normal lens. The image on the DX format is filling the same space as a 50 would on the FX format.
On a DX camera the 50mm lens is ideal because the image it replicates is close to normal. i.e. normal lens. The perspective is considered as you would see it in life. It would also be ideal on FX as the perspective is the same. Photographers prefer a slightly longer lens on FX because it eliminates unwanted background and maintained a comfortable working distance between the photographer and the subject. It has little foreshortening which is the type of distortion you will start to get with telephoto lenses. A slight foreshortening is preferred by many photographers. The wide f-stops produce less detail in the back ground. Also the greater the millimeter of the lens (telephoto effect) the more the backgrounds appear out of focus at a specific f-stop.
MK
 

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