Need advice on portrait lenses

Wasp · 09-19-2017, 12:21 PM - **1 Like**

An 85mm would fill the gap between the 50mm and 135mm perfectly. The Samyang/Rokinon is excellent value for money. Just bear in mind that it can be tricky to focus with that big aperture. The 70mm Pentax would be easier to handle in this respect.

On a (slightly) lower budget you can also look at the Jupiter 9 85mm f/2, but it is a bit of an acquired taste. Manual focus, manual aperture, M42 adapter means that you can't rush anything.

Last edited by Wasp; 09-19-2017 at 12:26 PM.

ChristianRock · 09-20-2017, 06:51 AM - **1 Like**

50mm is perfect for portraits on APS-C, I think. It is what I use all the time.
Use that for a while and see if you find the need for anything else.

**mikesbike** · 09-20-2017, 02:48 PM - **1 Like**

Your 50mm f/1.7, which I assume is a Pentax lens, since they made a couple of exceptionally fine ones, will indeed serve your stated purposes beautifully. This lens is actually sought-after specifically for such purposes. It is also a full-frame lens, so in case you should also acquire a FF body in the future, it will still be very useful with it, but not as much for portraits. If your lens is what I am thinking it is, consider your good luck- it is a keeper!

careaga · 09-20-2017, 05:44 PM

Originally posted by mikesbike

Your 50mm f/1.7, which I assume is a Pentax lens, since they made a couple of exceptionally fine ones, will indeed serve your stated purposes beautifully. This lens is actually sought-after specifically for such purposes. It is also a full-frame lens, so in case you should also acquire a FF body in the future, it will still be very useful with it, but not as much for portraits. If your lens is what I am thinking it is, consider your good luck- it is a keeper!

The lens came as part of the best deal I've ever gotten on Craigs List. It was on a Pentax ZX-5 and also came with a 28-200mm f3.8 Tamron AF, nice sturdy case and an auto winder...all for 75 bucks. If I ever decide to get back into film photography I have a nice upgrade from my K-1000.

TheOneAndOnlyJH · 09-22-2017, 02:16 PM - **1 Like**

I think you might do well with the 50mm f/1.7 you already have since it makes a pretty good portrait lens on APS-C cameras like your K-50. Portraiture is actually a very broad field, but your 50mm f/1.7 and 28-200 are perfect for figuring out where in the range you are happiest. It's all about perspective.

The first thing you'll have to decide is whether you looking for head, torso, or full body portraits. Another decision is if you want flat backgrounds (indoor) or natural backgrounds (outdoor).

Using your 28-200, take one picture close up (40-50mm) and then another farther away but zoomed in (80-90mm) to frame your subject the same. (Use the same aperture for both.) Comparing how they look will help you see how the perspective changes due to focal length. Zoom in on their face to see how the perspective changes the shape due to distance.
This link does a great job showing how perspective changes faces. He moves farther with each lens to frame the face the same, and as focal length increases his face 'fattens' up.* The comments under the article are pretty helpful too.

Next take a shot using your 50mm wide open at f/1.7 and at narrowing apertures (f/2.8, f/3.5, f/5.6, f/8.0). Comparing these can help you see how much you want the background out of focus.

Based on these two little trials, you can probably get an idea of what focal length and aperture range might make you happy.

*This is also why people say 'the camera adds 10 lbs'. You're used to seeing how you look in a mirror 3 ft away (6 ft between your eyes and your 'mirror image'), so a picture taken 3-6 ft away looks familiar. A picture on TV is usually shot from 10 or 20 ft away, so your face looks wider than you are used to seeing. (This is also probably why people are addicted to selfies, taken from less than 3 ft away.)

---------- Post added 09-22-17 at 05:48 PM ----------

Portraiture really is all about personal preference. Here's another link that compares perspective effects at different focal lengths using full torso shots outdoors. He's not looking at background blur so much as perspective and background size.

It seems a bit confusing at first, but there are a few concepts that are worth getting familiar with.
1) Moving farther from the subject and zooming in will make the background appear larger (though probably blurrier. See #2).
2) At the same aperture, a larger focal length will have a narrower depth of field, causing a blurrier looking background.
3) For a given focal length and aperture, moving the subject (and zone of focus) closer to the camera will make the background blurrier (but the subject will be larger).

Here is an online simulator with slider controls to help demonstrate. I knew the basic physics from school, but playing with the simulator really makes it obvious.

Wasp · 09-23-2017, 01:24 AM

Originally posted by TheOneAndOnlyJH

Here is an online simulator with slider controls to help demonstrate. I knew the basic physics from school, but playing with the simulator really makes it obvious.

Great link, thanks for sharing it!

My nerdy side can't help wondering how they do it.

09-22-2017, 02:16 PM - 1 Like	#20
TheOneAndOnlyJH Veteran Member Join Date: Dec 2013 Location: Buffalo, NY Posts: 351	I think you might do well with the 50mm f/1.7 you already have since it makes a pretty good portrait lens on APS-C cameras like your K-50. Portraiture is actually a very broad field, but your 50mm f/1.7 and 28-200 are perfect for figuring out where in the range you are happiest. It's all about perspective. The first thing you'll have to decide is whether you looking for head, torso, or full body portraits. Another decision is if you want flat backgrounds (indoor) or natural backgrounds (outdoor). Using your 28-200, take one picture close up (40-50mm) and then another farther away but zoomed in (80-90mm) to frame your subject the same. (Use the same aperture for both.) Comparing how they look will help you see how the perspective changes due to focal length. Zoom in on their face to see how the perspective changes the shape due to distance. This link does a great job showing how perspective changes faces. He moves farther with each lens to frame the face the same, and as focal length increases his face 'fattens' up.* The comments under the article are pretty helpful too. Next take a shot using your 50mm wide open at f/1.7 and at narrowing apertures (f/2.8, f/3.5, f/5.6, f/8.0). Comparing these can help you see how much you want the background out of focus. Based on these two little trials, you can probably get an idea of what focal length and aperture range might make you happy. *This is also why people say 'the camera adds 10 lbs'. You're used to seeing how you look in a mirror 3 ft away (6 ft between your eyes and your 'mirror image'), so a picture taken 3-6 ft away looks familiar. A picture on TV is usually shot from 10 or 20 ft away, so your face looks wider than you are used to seeing. (This is also probably why people are addicted to selfies, taken from less than 3 ft away.) ---------- Post added 09-22-17 at 05:48 PM ---------- Portraiture really is all about personal preference. Here's another link that compares perspective effects at different focal lengths using full torso shots outdoors. He's not looking at background blur so much as perspective and background size. It seems a bit confusing at first, but there are a few concepts that are worth getting familiar with. 1) Moving farther from the subject and zooming in will make the background appear larger (though probably blurrier. See #2). 2) At the same aperture, a larger focal length will have a narrower depth of field, causing a blurrier looking background. 3) For a given focal length and aperture, moving the subject (and zone of focus) closer to the camera will make the background blurrier (but the subject will be larger). Here is an online simulator with slider controls to help demonstrate. I knew the basic physics from school, but playing with the simulator really makes it obvious.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Replacing portrait lenses, need suggestions	AshleytheIslander	Pentax SLR Lens Discussion	9	07-23-2017 06:05 AM
Best Portrait Lens-Need Advice	giselag	Pentax K-3 & K-3 II	14	07-12-2017 09:40 PM
Sold lens ... now need advice on what I need	jpzk	Pentax SLR Lens Discussion	35	11-29-2009 10:32 AM
Need advice! Pentax K1000SE - $110 plus lenses, etc...	lattyday	Film SLRs and Compact Film Cameras	11	11-24-2009 06:23 PM
Hello! Need some advice for buying lenses.	Tiu	Pentax SLR Lens Discussion	7	07-13-2009 05:40 AM

09-19-2017, 12:21 PM - 1 Like	#16
Wasp Pentaxian Join Date: Mar 2017 Location: Pretoria Photos: Gallery Posts: 4,662	An 85mm would fill the gap between the 50mm and 135mm perfectly. The Samyang/Rokinon is excellent value for money. Just bear in mind that it can be tricky to focus with that big aperture. The 70mm Pentax would be easier to handle in this respect. On a (slightly) lower budget you can also look at the Jupiter 9 85mm f/2, but it is a bit of an acquired taste. Manual focus, manual aperture, M42 adapter means that you can't rush anything. Last edited by Wasp; 09-19-2017 at 12:26 PM.

09-20-2017, 06:51 AM - 1 Like	#17
ChristianRock Pentaxian Join Date: Jul 2013 Location: People's Republic of America Photos: Gallery \| Albums Posts: 9,912	50mm is perfect for portraits on APS-C, I think. It is what I use all the time. Use that for a while and see if you find the need for anything else.

09-20-2017, 02:48 PM - 1 Like	#18
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,562	Your 50mm f/1.7, which I assume is a Pentax lens, since they made a couple of exceptionally fine ones, will indeed serve your stated purposes beautifully. This lens is actually sought-after specifically for such purposes. It is also a full-frame lens, so in case you should also acquire a FF body in the future, it will still be very useful with it, but not as much for portraits. If your lens is what I am thinking it is, consider your good luck- it is a keeper!

09-20-2017, 05:44 PM	#19
careaga New Member Join Date: Dec 2015 Photos: Gallery Posts: 6 Original Poster	Originally posted by mikesbike Your 50mm f/1.7, which I assume is a Pentax lens, since they made a couple of exceptionally fine ones, will indeed serve your stated purposes beautifully. This lens is actually sought-after specifically for such purposes. It is also a full-frame lens, so in case you should also acquire a FF body in the future, it will still be very useful with it, but not as much for portraits. If your lens is what I am thinking it is, consider your good luck- it is a keeper! The lens came as part of the best deal I've ever gotten on Craigs List. It was on a Pentax ZX-5 and also came with a 28-200mm f3.8 Tamron AF, nice sturdy case and an auto winder...all for 75 bucks. If I ever decide to get back into film photography I have a nice upgrade from my K-1000.

09-23-2017, 01:24 AM	#21
Wasp Pentaxian Join Date: Mar 2017 Location: Pretoria Photos: Gallery Posts: 4,662	Originally posted by TheOneAndOnlyJH Here is an online simulator with slider controls to help demonstrate. I knew the basic physics from school, but playing with the simulator really makes it obvious. Great link, thanks for sharing it! My nerdy side can't help wondering how they do it.