Aperture for Portraits question

*MSM* · 08-12-2009, 10:28 PM

I hope someone can give me some guidance. I was taking a casual portrait of my son today. While post processing (sharpening) at 100%, I noticed that his left eye (distant) was sharper than his right (near). I thought at the time that his face was just slightly tilted with the left eye further away, but not by much. I was using a K10d with a SMC A 50 mm at f/4.0. I would have thought I could carry both eyes at f/4.0. I know with my 77 mm I have been burnt by leaving my aperture sub 2.8. I guess I must have focused on the left eye, when I should have focused on the near eye. It is not terrible and at a smaller print size probably undetectable. But, now that I can see it...I can't stop seeing it.

At a 100% view , am I expecting too much? I don't pixel peep, but I do like to zoom in while sharpening so I don't get too heavy handed. Should I be stopping down to 5.6 or 8? I have included the shot although I don't think one can see the difference. However, one can see the degree of rotation of my son's head. Thoughts are much appreciated.
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Name: _IGP2117.jpg
Views: 895
Size: 22.8 KB

kerrowdown · 08-13-2009, 02:02 AM

You try in PP just doing a little extra selective sharpening of the right eye area, via layers and see how it looks.

A great shot, try not to get too wrapped around the axle, as you say it's undectable on smallish prints. Next time out, try a smaller aperture and see, modern lenses no longer have the DOF scales they used too, which gave a rough rule of thumb in use.

*Ash* · 08-13-2009, 06:57 AM

I opt for getting DOF right in camera the first time, so the closer you get to the subject or the more telephoto you go with your lenses, the more you need to stop down - that goes for just about any photo.

Do the chimping while you shoot, particularly as you may not have the DOF scales on the lens to judge, so preview the shots and enlarge to see that it's adequately sharp before settling on the image.

*Wheatfield* · 08-13-2009, 07:28 AM

Shallow depth of field portraits require very careful setup, along with tremendous cooperation from the subject. With kids, it's best to stop down a little more, since they will rarely hold their head precisely where you want it. Even a slight turn of the head can be enough to knock one or both eyes out of focus.

Barnster · 08-13-2009, 07:05 PM

Originally Posted by MSM

I hope someone can give me some guidance. I was taking a casual portrait of my son today. While post processing (sharpening) at 100%, I noticed that his left eye (distant) was sharper than his right (near). I thought at the time that his face was just slightly tilted with the left eye further away, but not by much. I was using a K10d with a SMC A 50 mm at f/4.0. I would have thought I could carry both eyes at f/4.0. I know with my 77 mm I have been burnt by leaving my aperture sub 2.8. I guess I must have focused on the left eye, when I should have focused on the near eye. It is not terrible and at a smaller print size probably undetectable. But, now that I can see it...I can't stop seeing it.
At a 100% view , am I expecting too much? I don't pixel peep, but I do like to zoom in while sharpening so I don't get too heavy handed. Should I be stopping down to 5.6 or 8? I have included the shot although I don't think one can see the difference. However, one can see the degree of rotation of my son's head. Thoughts are much appreciated.
Attachment 41026

I probably would have gone to a deeper DOP like f5.6 or f8.0.And then focus on the closest part of the your subject.Practice makes perfect.So just practice,practice,practice.You'll get there!

K-9 · 08-14-2009, 11:07 AM

Sometimes it's not the aperture causing the blur, it could be slight camera movement or the subject moving.

*MSM* · 08-14-2009, 10:02 PM

Thanks for everyone's replies.

Originally Posted by Barnster

I probably would have gone to a deeper DOP like f5.6 or f8.0.And then focus on the closest part of the your subject.Practice makes perfect.So just practice,practice,practice.You'll get there!

You may be right. I will try 5.6 or 8.0.

Also as Ash mentioned it maybe that I was pretty close to my son and this made the dof smaller than I expected.

Originally Posted by K-9

Sometimes it's not the aperture causing the blur, it could be slight camera movement or the subject moving.

True. But, in this case, the left side of my son's face is tack sharp with the oof area on the right side only. Subject and camera movement would affect the entire image.

*Rich_A* · 08-18-2009, 01:33 PM

This is a great thread. I actually do a fair bit of portraiture for my job (albeit mostly the canine variety) and I had to figure this out as I went. There are a few questions to answer before deciding on the appropriate aperture for a portrait:

1) What focal length lens are you going to use? This deals mostly with the type of portrait. If you're wanting to shoot close up and personal and just frame the head and tops of the shoulders, I find a 50-75mm lens gives a decent working distance while keeping things fairly personal. You can of course, move further back and choose a longer focal length, maybe 100-135mm (zooms are a great way of framing these types of shots).

2) Desired of depth of field? This is where the creative control comes in. For me, I like to have the majority of the head "in focus" that is, without major blurring of the major facial features. For animals, especially dogs, you really want to have the nose in focus as well as the ears and with larger dogs, you can be talking about 10-12 inches for this span.

Once you decide these two basic criteria, a quick check of your depth of field calculator, I really like The Online Depth of Field Calculator. If you have a lens with DOF markings you can do this on the fly until you get the hang of the differences.

I can simplify this based on my field experiences to say that when I shoot a medium-sized animal, I try to use a 50mm lens on my APS-C sensor camera making it an equivalent 75mm lens. My working distance is usually in the 6-8 foot range and I shoot at around f/8 for a sufficient DOF. This provides a very normal-looking perspective. If I want a blurrier, less distracting background, I can always reposition the model so they are further away from the objects in the background. I find I prefer this over opening up the aperture as I begin to lose the desired DOF.

For a more creative portrait look, however, I'll switch to a longer focal length (75-90mm) and move back to around 10-12 feet and shoot at the same aperture (f/8), you have a bit more leeway regarding background objects as the longer FL will blur them more easily.

I rarely shoot normal portraits at less than 50mm or longer than 135mm (actual settings on the lenses, not crop-factor numbers) as I find that <50mm leads to a bit too much distortion and >135mm requires too fast of a shutter speed to avoid camera shake. This is a very conservative approach to portraiture, but I'm not going for creative composition but instead a very straightforward setup that allows me to get very predictable (some might rightfully say boring) results. It's at least a good starting point before you jump into more unique options.

*MSM* · 08-21-2009, 01:22 PM

Rich A: Thanks for the nice reply. I was using a 50 mm focal length. I think you may have answered the question I couldn't articulate. You state that your working distance with f/8 is 6-8 feet. I was probably 2-3 feet away with an aperture of f4, which explains the limited depth of field. Seems that I needed to step back and step down on the aperture. Thanks.

DAZ · 08-21-2009, 04:01 PM

Originally Posted by MSM

Rich A: Thanks for the nice reply. I was using a 50 mm focal length. I think you may have answered the question I couldn't articulate. You state that your working distance with f/8 is 6-8 feet. I was probably 2-3 feet away with an aperture of f4, which explains the limited depth of field. Seems that I needed to step back and step down on the aperture. Thanks.

Here is an online Depth of Field Calculator. Online Depth of Field Calculator

You can play with it to get a feel for the DOF others are talking about. When you play with it you will see that the DOF was very small for the photo you were taking and when you add focus error (there is usually some) it was good you did not have more out of focus.

Also do forget you are getting some distortion to his face and you will get less of that by moving back. Here is some info on perspective distortion. On faces it make the nose look bigger and the face flatter.
Perspective distortion (photography) - Wikipedia, the free encyclopedia

DAZ

MikePerham · 08-22-2009, 10:14 AM

Originally Posted by DAZ

Here is an online Depth of Field Calculator. Online Depth of Field Calculator

You can play with it to get a feel for the DOF others are talking about. When you play with it you will see that the DOF was very small for the photo you were taking and when you add focus error (there is usually some) it was good you did not have more out of focus.

Very useful tool. I just played with it to determine that with a 55mm lens at 5 feet and f1.4 the DOF is next to nothing. At f2.8 it is about 4 inches ...usable for portraiture.

DAZ · 08-22-2009, 11:10 AM

Originally Posted by MikePerham

Very useful tool. I just played with it to determine that with a 55mm lens at 5 feet and f1.4 the DOF is next to nothing. At f2.8 it is about 4 inches ...usable for portraiture.

If you like that one you will love this one. Photography Calculators - Web Links

This one explains less but it will do more things. Just remember that the “Focal length multiplier:” for Pentax cameras is 1.5.

DAZ

Mechan1k · 08-29-2009, 02:29 AM

Have had this issue many a time ... and i realise it all too late when i bring the shots up on the PC later on.

I now stop down a little more for portraits ... and use bounce flash as well to just freeze the shot if needed ... but in doing so I was getting everything in focus on my subjects face ... but still have background nicely out of focus to give some pop to the image.

I use shallower DOF for artier shots now where it suits it better. On the odd occasion now I will be fairly wide-ish open for some portraits ... but that's when i can't use flash ... and then i get a lot of them to make sure I at least get a few good ones in.

MikePerham · 08-29-2009, 08:35 AM

Originally Posted by DAZ

If you like that one you will love this one. Photography Calculators - Web Links

My cell phone is used as a phone, but a friend of mine just purchased an i-phone and showed me some of the applications built in to the phone ...even has a GPS application. This type of calculator would be a great app for the i-phone and it's competitors so one could have a pocketable version to use in the field.

EricT · 08-30-2009, 02:55 AM

Originally Posted by MikePerham

My cell phone is used as a phone, but a friend of mine just purchased an i-phone and showed me some of the applications built in to the phone ...even has a GPS application. This type of calculator would be a great app for the i-phone and it's competitors so one could have a pocketable version to use in the field.

Funny you should mention that. I just made a dof calculator for Google's Android phones. If there's any interest, I'll polish it a bit and release it. You can find a calc for the iPhone on dofmaster.com