Pentax 50mm 1:2 SMC Pentax-M. Any good for portraits?


campbew

Link Posted 18/01/2014 - 15:51
Many thanks

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SteveEveritt

Link Posted 18/01/2014 - 16:31
apparently the favoured length for portraiture is around the 70-135mm range so, taking into consideratioin your 1.5x crop factor, a 50mm will have the equivalent look of a 75mm lens, very definitely in the range.
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"Life is what happens to you while you're busy making other plans" (John Lennon)
Last Edited by SteveEveritt on 18/01/2014 - 16:32

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LennyBloke

Link Posted 18/01/2014 - 16:52
Agreed - I think most of the Pentax 50mm's are very suited for portraits
LennyBloke

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richandfleur

Link Posted 19/01/2014 - 09:56
SteveEveritt wrote:
apparently the favoured length for portraiture is around the 70-135mm range so, taking into consideratioin your 1.5x crop factor, a 50mm will have the equivalent look of a 75mm lens, very definitely in the range.

I've kinda got an issue with this line of thinking, but at the end of the day, a 50mm lens on a crop sensor APS-C sensor/body does produce fine portrait images.

Different lenses compress the image to different degrees (distance between close and far away objects) more with higher focal lengths. So a 300mm lens compresses everything up and a 10 or 18mm lens will accentuate near items much more, even to the point of barrel distortion.

It's the sweet spot of this that makes it a good portrait lens, with regards to the end result on a persons head. Too small a focal length and they'll look bulbous, with big foreheads etc, and too large/long a focal length and their face will look very flat and fat.

My issue the 50mm is that the crop factor limits the field of view only, so really it doesn't actually come into the equation with regards to the effect that lens is going to give on a persons face. A 50mm optic is still just that even when it's on a crop sensor camera.

The caveat may be that in standing further back to achieve the same field of view you somehow create a different image characteristic. That part I haven't really thought right through. Fully open to comments/corrections on the above. I think it makes an interesting discussion.

Anyhow, regardless, the 50mm's take good portraits on Pentax DSLR cameras.

johnriley

Link Posted 19/01/2014 - 10:02
Quote:
The caveat may be that in standing further back to achieve the same field of view you somehow create a different image characteristic. That part I haven't really thought right through. Fully open to comments/corrections on the above. I think it makes an interesting discussion.

You do need to think this through, because your whole post has several misunderstandings in it.

The only way to change perspective is to alter the distance you are from the subject. That's why a 50mm lens will give a more pleasing look to a face than going in close with an 18mm lens. You are further away from the subject so the perspective changes. This is what gives the apparent compression with long lenses. If you enlarged the centre of a wide angle lens to match the FOV of a long lens, then the compression would be exactly the same, assuming that is you are stood in the same place for the two images.

We've covered this in excruciating detail in a recent thread.
Best regards, John

ChrisA

Link Posted 19/01/2014 - 14:30
johnriley wrote:
We've covered this in excruciating detail in a recent thread.

I'm getting flashbacks now...
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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johnriley

Link Posted 19/01/2014 - 14:43
You well might Chris.
Best regards, John

gartmore

Link Posted 19/01/2014 - 15:36
Flashbacks, I'm sitting very still and quiet under the kitchen table
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

gartmore

Link Posted 19/01/2014 - 15:37
Any way I think your lens will be perfect and a 50 is my 'go to' lens for portraits.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

Algernon

Link Posted 19/01/2014 - 16:17
I presume that you mean this thread in which almost EVERYONE was wrong and I was right!
If there was a competion for the dumbest forum this one would probably win

I would have expected that by now you would have all read a basic book on photographic perspective

Richard is of course spot on Glamour photographers have long since realized that a wide angle lens makes peoples boobies (mostly women) look much bigger. You can't get the same effect with a standard/tele lens no matter where you plonk it. This has been done to the extreme by sites such as pinupfiles (dot com warning distorted nudity). Bill Brandt also did it.

I've just taken this quick shot of a 3ft ruler with a Sigma 10-20mm at 10mm and 20mm on a tripod at a fixed position. I would have liked to have used 10mm and 35mm, but didn't want to change the lens. So rather than a comparison between WA and STD.... It's between two WA's.




You can see that even from the same distance it's the lens that fixes the perspective, you can't enlarge the 10mm shot to look like the 20mm shot because the included angle of the sides of the ruler is different.

The included angle of the sides of the ruler are...
10mm = 27.5deg
20mm = 17.1deg
These would stay the same on enlargement due to the different perspectives.

There have also been some shots of castles on here recently showing quite clearly the perspective ONLY obtainable from a wide angle lens.
Very often the Vanishing Points from a WA shot are actually within the frame or just outside like this.... This isn't distortion it's WA perspective.




Where JR is confused is with 2D Flat Copy which has the VP's at Infinity so you can enlarge that to get the equivalent view to a tele, because perspective isn't involved.

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 19/01/2014 - 16:19

johnriley

Link Posted 19/01/2014 - 16:34
Algi, you moved the camera. You really are off on a tangent with this and you can't see why. You are flying in the face of what every single photographic writer knows.

For the last time, perspective depends upon your distance from the subject, nothing else.
Best regards, John

gartmore

Link Posted 19/01/2014 - 16:36
Algi, please just stop. You alone have a unique perspective on perspective
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

Algernon

Link Posted 19/01/2014 - 17:02
OK Lets leave it at that, but because I've already enlarged the 10mm LHS to nearer to the 20mm RHS (but still not enough) I'll post that image because I'm sure that other people are interested in the practical side of photography.

The camera/tripod wasn't moved between shots. A Novoflex 5 B&S head was used and it has gone sightly off vertical.
A Pan and Tilt would have been better.

The test is very simple for anyone else to do.
Takes about 2 mins. use a piece of wood if you
haven't got a 3ft ruler.

You can see clearer that the perspective isn't the same for a 10mm and 20mm from the same distance.

I might continue this on a blog.




--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 19/01/2014 - 17:18

Smeggypants

Link Posted 19/01/2014 - 20:37
Algernon wrote:
I presume that you mean this thread in which almost EVERYONE was wrong and I was right!
If there was a competion for the dumbest forum this one would probably win


Ok then so tell me why the perspective doesn't change when I zoom in and out on EVERY ONE of my zoom lenses, if I don't change the distance from the subject?
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283

ChrisA

Link Posted 19/01/2014 - 21:23
Doh, I looked.

Flashbacks no longer...
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.
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