[lguckert79]

well i have some $$ saved up for a new lens and was thinking of either one of the new da 50mm or an fa 50mm either one or one of the rokinon 85mm manual A pin lenses i need a good portrait lens with a fast apture and not sure what i should get. because if i get the 85 with the crop factor it will frame like a 127mm and if i get the FA it will be like a 75mm but if i get the DA I think that lens is set for crop sensor so i would get a standard 50. Now with the 85 it has manual but with the 50's it is auto and i have been reading the reviews and they all seem to say its hard to hit good focus on the 85 and this would not be an issue on the 50's but back to my ?? what one would you say would be better for portrait photos the 85' the fa' or the da????? i dont know I need other input thanks

[adpo]

a 50 is a 50, so you'll get the same FoV between the two 50mm lenses. crop factor only works when going between actual sensor sizes, not for lenses.

in any case, you seem like you have some lenses already in that focal range. try taking them out and seeing which you prefer more and deciding on which focal length based on that. Personally, I'd take the 85 as I typically have the amount of space needed to work with such a long lens and I prefer the mid-tele look you get from that focal range. YMMV

[Just1MoreDave]

Forget about the crop factor and different lens types. A 50mm lens will look the same to you whether it's DA or FA, as long as you're using the same camera for both.

If you plan on portrait use, the difference between 50 and 85 is about how far away you are from a subject and how much of the subject is in the frame.

A lot of flashes start to fall off at higher focal lengths so that's a concern for flash users.

[androsokin]

As far as I understood you need a portrait lens. 85mm is a portrait focal length with minimal distortion so you can make face portraits with it. 50mm doesn't intend for face portraits, may be waist-high portraits only, because of aberrations.
http://en.wikipedia.org/wiki/Portrait_photography#Lenses

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Last edited by androsokin; 10-11-2012 at 01:53 AM.

[DSims]

It looks like you have lenses that cover all these focal lengths already, so you know what 50mm vs. 85mm will give you in terms of FOV.

The 85/1.4 will definitely give you the most subject isolation from the background. It will go beyond anything you have right now. I haven't owned the Samyang (Rokinon), but I do have the FA*85/1.4. So if you can deal without the AF it's probably a good choice. Otherwise I'd think about the DA50/1.8.

[hoanpham]

If you don't have a 50mm, get it first, FA50/1.4 or DA55/1.4 or sigma.
The need of a 85mm will come far later.
Don't spend money on thing you may not like or not regularily use.

Any lens can give a good portrait.

[donfenix]

The "ideal" focal for portrait is roughly between 70 to 100 in full frame (ie between 45 to 66 in APS-C). Any of the two 50s, whether DA or FA on your cropped sensor will give you the same 75mm in FF equivalent, which sits in the ideal 70-100 range. Avoid the 85, as it will be equivalent to a 127 as you guessed, which will make faces appear flattened and unnaturally wide, plus you won't be able to use it indoors, unless you live in a mansion or go into a different room to put enough distance between you and your subject. If you are picky and really wanna be closer to the middle of the "ideal" range, get yourself a 55 (82.5 equivalent). You can do that two ways: get the expensive and high-tech DA*55 F1.4, or if you are willing to put up with manual focusing, go to eBay and get the cheap but excellent Super Takumar 55mm F1.8 (you'll need an M42 adapter).

[donfenix]

BTW, here is an excellent illustration of what you can expect from various focal lengths:

The Ideal Focal Length for Portraiture: A Photographer's Experiment

[Sandy Hancock]

Well I like portraits taken with longer focal lengths. Some of my favourites have been with my FA77, DFA100 and Sigma 70-200 (at the longer end). That equates to well over the supposedly "ideal" 70-100mm full frame equivalent.
Take photos. Be creative. Don't follow formulas

[ChooseAName]

It depends on the typical context of your photography. Mostly what I do is documenting my own family activities, which means lots of action shots of a 3 year old and some candid portraits when I can get her to sit still A lot of times this takes place outside and I prefer my M 85/2 then (actually I prefer my M 85/2 most of the time regardless ). 50 mm might be slightly more versatile in that it's easier to get full body shots, or more of the background for better context. Also if you ever need to take small group shots, a 50 would be better for that. Having said all that though, I love the 85 mm focal length and like to "make it work" in situations that I said the 50 would be better for.

Depth of focus will be very thin at f/1.4 on 85 mm. Do you have a good focusing screen?

[Lowell Goudge]

before selecting the lens, consider your shooting situation

image size = subject size x focal length / distance

your image size is 24 mm (long dimension of APS-C sensor
Subject Size is about 400mm for head & shoulder, 1 meter for half body shot and 2 meters for full body (tall person)
If you consider your lenses, you get the following:


head shot shooting distance 50mm lens 0.830 meters, 85 mm lens 1.4 meters
1/2 body shooting distance 50mm lens 2.1 meters, 85 mm lens 3.55 meters
full body shooting distance 50mm lens 4.2 meters, 85 mm lens 7.1 meters

when picking the lens you need to consider also the working space you need. the above figures will help you decide.

Also, when considering a fast portrait lens, assuming that you change your shooting distance proportional to the change in focal length, the depth of field is almost constant. BUT due to the different perspective each lens will offer, at the different shooting distances, the longer lens will appear to have better bokeh because while the background is just as blurred (each detail at its edge) the longer lens makes the background pattern bigger and less confusing.

[Just1MoreDave]

It depends on the typical context of your photography. Mostly what I do is documenting my own family activities, which means lots of action shots of a 3 year old and some candid portraits when I can get her to sit still A lot of times this takes place outside and I prefer my M 85/2 then (actually I prefer my M 85/2 most of the time regardless ). 50 mm might be slightly more versatile in that it's easier to get full body shots, or more of the background for better context. Also if you ever need to take small group shots, a 50 would be better for that. Having said all that though, I love the 85 mm focal length and like to "make it work" in situations that I said the 50 would be better for.

Portraits involve a lot of relationships, like focal length to image size or subject to the viewer or whatever. There's also some relationship between photographer and gear, which contributes to the ultimate image. When I have portrait experience with a lens and have taken some good shots with it already, I don't have to think consciously about every element of the shot and how they work at a certain focal length. That gets me beyond the lens and able to figure out what I want to take a photo of.

[Lowell Goudge]

When I have portrait experience with a lens and have taken some good shots with it already, I don't have to think consciously about every element of the shot and how they work at a certain focal length. That gets me beyond the lens and able to figure out what I want to take a photo of.

Dave, while I agree, this is not what the OP has asked, he has not yet gotten his lens, and the debate is about what he should get. from my perspective, it is at the planning stage that he needs to sit down and think about what he is shooting. if he is, for example in a studio, and wants to use an 85 for full body shots, the shooting distance, as I indicated above has serious impacts on his studio. Many may not have a studio with in excess of 22 feet between the shooter and subject. that would imply likely a 20 x 30 foot room, so until the OP decides what types of portraits etc, and picks a lens that suits his shooting situation he will never become familiar with it.

[johnyates]

The best bang for your buck would be one of the fast 50/55's available.

And, Lowell's advice about shooting distance is bang on--with the longer lens not having adequate shooting distance can be a problem. With the shorter lens, you can always back up a bit and crop in PP.

If I was picking only between the two, I'd go for a 50 or 55. Otherwise, I'd give some very strong consideration to the 70mm. It's a great lens and a good compromise regards shooting distance.

[lguckert79]

thank you for all your answers, "lowell" you brought up a very good point. The distance to subject is some thing i really had to think about and i do have a vivatar 50mm f1.7 and the lens does a good job and i like the way it frames, and the results it gives. I just dont like the manual focus part so I think im going for the 50mm fa or da. Now what one should i get? The da or fa the new review on here says that the da gives better results but what if pentax comes out with FF in the next 3 years then im stuck with a lens that won't work on that and i will have to reinvest in new lenses when all but 2 lenses i have will work on ff so im leaning toward the FA 50 what do you all think???