Portait lens on non-full frame

eravedesigns · May 27, 2007

Hello

I have heard that an 85mm is a perfect lens for portraits but my question is that 85mm on a full frame or 35mm? if this is true then would a 50mm be good for portraits because my camera has a 1.6 multiplier on it?

JIP · May 27, 2007

A fast 85 is still a good portrait lens with a digital sensor Even with the crop factor. I see you have Sony the lenses you have probably seen mentioned are a Canon 85 1.8 or a Nikon 85 1.8 both of wich are excellent portrait lenses but they are also very fast lenses I do not know if Sony has an equivalent if they do it too would be an excellent portrait lens.

Sw1tchFX · May 27, 2007

Minolta would have made an 85 f/1.8 or 1.4.

eravedesigns · May 27, 2007

They have a 50mm 1.4 for around $300 which I can do but their 85mm is a 1.4 but its also $1,300 and i cant afford that. Would you say i can get the 50 and be fine and try to find an 85 thats cheap and i would also have a good portrait lens. Basically will the 50mm work for portraits?

Alpha · May 28, 2007

I personally like to work up close...it's easier to keep the rapport going. However, 85mm I think is a great length. 50mm is far too wide for most people.

Treymac · May 28, 2007

Sorry to hijack this thread but I'm confused, doesn't the mm you set it on depend on how far away you are? So 85mm would only be good if your standing at a certain distance? And what does full frame mean?

Alex_B · May 28, 2007

Treymac said:
Sorry to hijack this thread but I'm confused, doesn't the mm you set it on depend on how far away you are? So 85mm would only be good if your standing at a certain distance? And what does full frame mean?

If you only talk about that someone's head should fill the frame, that is true, with an 85mm you then have to step further back than with a 50mm.

But the two images you then produce, although the main subject might be of the same size in the final image, they will look substantially different, since the distance to the subject matters in terms of perspective.

Take for example a tree and a mountain in some landscape:

a) If you are far away from the tree, the tree will be small and the mountain behind it will look large in comparison to the tree.

b) if you move close to the tree, then the tree will appear much larger and the mountain, in comparison, rather small (since relatively speaking you haven't gotten that much closer to the mountain).

now, if you take a picture of a) with a long lens, so that the tree fills the frame and b) with a short lens, so that the tree fits the frame, you will get two totally different images.

Don Simon · May 28, 2007

If you can accept something not quite so fast, but in a nearby focal length and for a lot less, a macro lens like the Tamron 90mm f/2.8 could perform quite nicely as a portrait lens. Or for a lot less you could do what I did, get a Russian rip-off of a Zeiss design and mount it with an adapter, but it doesn't make for the most convenient shooting style.

eravedesigns · May 28, 2007

MaxBloom said:
I personally like to work up close...it's easier to keep the rapport going. However, 85mm I think is a great length. 50mm is far too wide for most people.

On a full frame or ?

Mike_E · May 28, 2007

Full frame means the size of the sensor, in other words the full frame sensor in a Digital is the same size as a negative on a 35mm film camera. On a 1.5 crop factor the sensor is 2/3 the size of a 35mm film negative. The term 'crop' is used because the resulting picture from one of the 1.5 CF cameras looks like it has been cropped from a Full Frame. There is no loss in quality (to speak of unless you are printing larger than 4 feet and then looking really close).

On the perspective thing, think of some ones' nose as the tree and their face as the mountain. You really don't want their nose to look out of proportion so it'd better to step back a little (working in close is a subjective thing and something you'll have to experiment with yourself). A 50mm will do fine on a 1.5 CF sensor. An 85mm would approximate a 135mm used for film which was also considered a good portrait lens. 70mm approximates the 105mm which can be done a couple of ways.

mike

Big Mike · May 28, 2007

The reason (well one reason) that people say that 85mm to 100mm is good for portraits, is that there is no 'wide angle distortion'. You wouldn't want to take someones portrait with a 14mm fish-eye lens...because they would look ridiculous. Well at 24mm...there is still some distortion...at 50mm there is even less and at 85-100mm it's all but gone.

Wide angle lenses tend to accentuate near-far distance. For example, the distance from the front to the back of a person's nose. If you are up close with a wide angle...their nose looks bigger. On the other hand, a telephoto tends to compress the distance...which is often a more attractive look for people. So if you could shoot someone with a 300mm lens...it would look great...but you would have to be rather far away from them.

As far as I know, the perspective distortion doesn't actually change if you use the lens on a 'full frame' (35mm film) or a cropped sensor camera. So you still want to use an 85-100mm lens. However, distortion is more pronounced at the edges of the frame...and since the crop factor cameras 'crop' the edges...less distortion is visible...so 50mm might work just fine.

Mike_E · May 28, 2007

Big Mike is correct, perspective is only changed by the distance from the subject to the sensor/negative. Neither lens or frame size has anything to do with it.

mike

eravedesigns · May 28, 2007

Ha thanks for all the comments. I was really just asking is a 50mm going to be a nice portrait lens I know why that range is good because like you said there is no distortion but just in general would you shoot with a 50 or an 80 on a sensor with a 1.5 crop?

DeepSpring · May 28, 2007

I shoot most of more portraits with either a 50mm 1.8 or my 70-200mm f/4 L at around 100-135mm on an xt so I do have the crop factor.

Big Mike · May 28, 2007

but just in general would you shoot with a 50 or an 80 on a sensor with a 1.5 crop?

There is no right or wrong...it's all about personal taste and style. If you like to work with a 50mm, the go for it. If you like a longer lens (and have room to use a longer lens) then do that.