What f/number is best for portraits?

[kencaleno]

Originally Posted by 49erbruin

I've been wrestling with this too. My main subject is my ~1 1/2 year old daughter who, of course, doesn't stay still for long. I was shooting her at ~f/2.5 with my 50 mm 1.4, but the photos weren't as sharp as I felt they should be with that lens.

A photographer friend suggested I 1) Try practicing at least at f/4 for a bit, since I'm not a super-experienced photographer; 2) DON'T use the center focus point and use switch to the correct point instead and 3) move my auto focus to AI Servo on my Canon XTi to help to better track my toddler.

I tried this yesterday and got MUCH sharper shots and good bokeh too! Hope that helps...

Wrong-it is better to only use the centre focus point; here's why:

In your camera’s viewfinder, depending on camera-flagship models generally have many focusing spots, and lesser, entry-level dslr’s will have around 5 focusing spots. With lens wide open, any of these spots can be used for selecting where to auto focus-But, depending on maximum aperture of lens in use, the ones you are able to use get fewer. Top-of-the-line cameras will only have the centre spot usable at F8,and entry level cameras at F5.6, and less than that, even these single spots aren’t reliable.]
Actually it is more beneficial to set auto focus by the centre spot, then re-compose, rather than use the peripheral spots-The reason being that only the centre spot has vertical and horizontal pixel rows. This means that if you use the peripheral spots (top and bottom spots have horizontal pixels only and right and left spots have vertical pixels only) To focus, you must have a part of the scene crossing a line of pixels at 90 degrees, and the centre spot gives you a more accurate reading ,having both vertical and horizontal pixels)

[hermanau]

I think this is one of those topics that's been discussed to death over and over again if you're talking about the focusing technique. Here's one of the pages that might get you re-think what you firmly believe if you haven't came across it yet: Why Focus-Recompose Sucks

I'm not entirely buying the article, but I can see how re-composing can mess up a shot under certain circumstances especially when you shoot wide open. I use a combination of re-composing, moving the focus spot, and also rely on the Nikon 3D tracking at times. I shoot weddings and engagements, and things can happen fast. Sometimes you don't get the luxury of focusing on the eyes and recompose 'cause the subject might have already moved by the time you recompose. But then again, let's back to the original topic:

I'm a firm believer of "nothing is the best" in photography. I think you'll find plenty of articles that tell you to go with F8 and a longer lens, or at least a F/5.6, and then again you might hear another professional say he/she only shoots wide open. At the end of the day, it really depends on what you are trying to achieve with whatever gear you have in your hands. If you think that F/2.8 is getting only the eyes in focus but the ears look soft and you don't like it, then try a smaller aperture; if you're shooting F/5.6 and you want to be a little creative and try a narrow DoF, then shoot wider. Go out there, experiment, have fun and enjoy the learning process.

Originally Posted by kencaleno

Wrong-it is better to only use the centre focus point; here's why:

In your camera’s viewfinder, depending on camera-flagship models generally have many focusing spots, and lesser, entry-level dslr’s will have around 5 focusing spots. With lens wide open, any of these spots can be used for selecting where to auto focus-But, depending on maximum aperture of lens in use, the ones you are able to use get fewer. Top-of-the-line cameras will only have the centre spot usable at F8,and entry level cameras at F5.6, and less than that, even these single spots aren’t reliable.]
Actually it is more beneficial to set auto focus by the centre spot, then re-compose, rather than use the peripheral spots-The reason being that only the centre spot has vertical and horizontal pixel rows. This means that if you use the peripheral spots (top and bottom spots have horizontal pixels only and right and left spots have vertical pixels only) To focus, you must have a part of the scene crossing a line of pixels at 90 degrees, and the centre spot gives you a more accurate reading ,having both vertical and horizontal pixels)

[swampyJ]

Frist off let me say thanks to all for speaking of this matter of what would be the best lens and f/__ for blur and photoing people . I have a canon T1i a 18-55mm f3 -5 and a 70-300mm f 4.5.
I can knot pay that price for a ( L ) lens . I have looked at the 50mm F1.4 but i heard and read so many bad reveiws on it im scared of it . i looked at the 50mm f/1.8 and some say its cheap so i say hmmm what do you do . I all so looked at the 85mm 1.8 . i shot with a asp-c 1.6 x . is there a good zoom that will blur the back ground that is not a ( L) price . looking for some thing indoors low light shoooting are in and out doors (no flash) . one more thing . do i need a wide angle to take full bodys . and are can i use a wide for head & shoulder shots are the other way around . one lens for full lenght shots and head and shoulders

thanks to all for adding info to this

[djotaku]

Here's another suggestion - the f/stop is not the only way to change apparent depth of field. You can go to f/4 or even f/8 to make sure the face is wholly in focus and still get a "pleasant" blurry background if you switch to a more telephoto lens or have the background further away.

[bobby62914]

Originally Posted by swampyJ

Frist off let me say thanks to all for speaking of this matter of what would be the best lens and f/__ for blur and photoing people . I have a canon T1i a 18-55mm f3 -5 and a 70-300mm f 4.5.
I can knot pay that price for a ( L ) lens . I have looked at the 50mm F1.4 but i heard and read so many bad reveiws on it im scared of it . i looked at the 50mm f/1.8 and some say its cheap so i say hmmm what do you do . I all so looked at the 85mm 1.8 . i shot with a asp-c 1.6 x . is there a good zoom that will blur the back ground that is not a ( L) price . looking for some thing indoors low light shoooting are in and out doors (no flash) . one more thing . do i need a wide angle to take full bodys . and are can i use a wide for head & shoulder shots are the other way around . one lens for full lenght shots and head and shoulders

thanks to all for adding info to this

The 50mm f/1.8 is inexpensive and hardly an engineering marvel. However, don't be afraid of it. It is the best lens you can buy for under $100. Okay, that is faint praise, but it still produces excellent photos.

The first one I bought was awful and I thought it was a junk lens. Better photographers than me kept saying it was good so I took it back to the dealer. He tested it and found it was defective and replaced it.

When you look at photos it will never pop into your mind, "That looks like it was taken with a $100 lens."

I have read good things about the 85mm f/1.8 and I have used the EF-S 60mm f/2.8 Macro and it is fabulous.

[agresbach]

Originally Posted by djotaku

Here's another suggestion - the f/stop is not the only way to change apparent depth of field. You can go to f/4 or even f/8 to make sure the face is wholly in focus and still get a "pleasant" blurry background if you switch to a more telephoto lens or have the background further away.

very good point. i'm a big fan of using my telephoto zoomed in to get the same effect but not having to worry about not focused subject .

[Rudyumans]

Originally Posted by Fotogreen

This might sound dumb but when you say focus on the eyes how do you do it say for example one is using one of the focus points?

If the eyes are parallel to the camera, it doesn't matter. Otherwise, focus on the eye closes to the camera. Use the center focus point. Better yet, focus manually.

[jegoldston]

i actually have the canon prime 50mm /1.4 and it was great when i 1st got it.
however, i started having focusing issues that i didn't realize until i was in post-process. i ONLY manually focus now - that helped a little. when i bought that lens, it had good reviews, so now i'm wondering... hmmm.

anyway, my camera is a low-end dslr...soooo, i don't know if it's the lens, or the camera, or that camera with that lens. all i know is i can't afford a better cam right now, and how frustrating it is to take 400 shots and end up having only 100 w/ the eyes in focus. errg.

i read an article that i posted a while back that had good info about 'that camera and that lens' issue (sorry, don't remember the link).

I have had to use mostly f/4 with what i have...rarely (and only in an extreme close up) do i go lower.

[Bluiz]

Let's see, i'd say f/4 or 5.6 and for anyone concerned about camera shake when shooting handheld, look up the video "Da Grip" hosted by Joe McNally. He shows a great way of shooting at smaller fstops while keeping steady!

[Stampeder]

My test had shown that you are correct. I try the suggestion from the article Why Focus-Recompose Sucks, it cannot beat the sharpness of using center focus and re-compose. Thanks for your input on this.