Shooting 2.8 or wider?

mpriest13

What is the secret to getting tack sharp photos using F2.8-F1.4. I am using and love my 50mm f1.4 but more often than not I get quite a few barely out of focus pictures. One eye more sharp than the other etc... I just can't seem to get the entire face really sharp. Help!

jeffreaux2

You will need to keep the eyes in the same plane as the sensor at those apertures. F2.8 isn't all that difficult, but F1.4 and 1.8 will require some care.

Focal length and distance will also play a big role.

F2 85mm

gvf

Use a tripod.

scottkwest

leaning away from focus...
One gotcha I keep running into...

I often spot focus, usually on the eyes, and then re-frame to shoot. Trouble is I often lean slightly forward or backas I re-frame. Don't do this

And yes, the DOF is so narrow it often doesn't work well with people.

The sharpest focus the lens can achieve is usually around F/5.6 for a fast lens. This means that not only is the DOF less at F/1.8 or F/1.4, but the sharpest plane isn't quite as sharp as the sharpest plane at 5.6.

Nikolai

I tend to shoot at f/4 or f/5.6 if I'm shooting at a close distance (less than 15ft) which is usually the case with 50mm (I use f/1.4 version) to achieve two goals
1) ensure my lens at its sweet spot
2) provide "full face" DOF

I shoot more open with 70-200/2.8 when I'm shooting outdors since I typically can afford a greater distance between me and my subject.

HTH

divamum

scottkwest wrote:

One gotcha I keep running into...

I often spot focus, usually on the eyes, and then re-frame to shoot. Trouble is I often lean slightly forward or backas I re-frame. Don't do this

re-framing and unintentionally shifting the plane is one of my big gotchas too - I'm learning not to do that...

I LOVE shallow DOF portraits and will always shoot as wide open as I dare, especially in natural light (the effect never pleases me as much in studio conditions). Yeah, it means tossers (although happily me keeper rate is constantly growing), but I really love the way it looks.

I still can't decide if I can live with only the leading eye sharp; I think it depends on the context. I certainly don't mind shoulders, chins and ears melting away into softness.

pathfinder

Nikolai wrote:

I tend to shoot at f/4 or f/5.6 if I'm shooting at a close distance (less than 15ft) which is usually the case with 50mm (I use f/1.4 version) to achieve two goals
1) ensure my lens at its sweet spot
2) provide "full face" DOF

I shoot more open with 70-200/2.8 when I'm shooting outdors since I typically can afford a greater distance between me and my subject.

HTH

I agree with Nik, that I prefer to use f4 or f5.6 for people if I want both eyes or eyes and mouth sharp.

When I try to shoot at f1.4 or f2 at less than 60 or 8 feet, DOF is really shallow, I cannot just wing it, but have to be quite meticulous about focus.

marikris

I found this site earlier http://www.dofmaster.com/doftable.html - The Depth of Field Table.

You plug in your camera and focal length and unit, and it creates a table.

I tried to read it, but it's all Greek to me

I guess my personal "circle of confusion" is quite large...

adbsgicom

marikris wrote:

I found this site earlier http://www.dofmaster.com/doftable.html - The Depth of Field Table.

You plug in your camera and focal length and unit, and it creates a table.

I tried to read it, but it's all Greek to me

I guess my personal "circle of confusion" is quite large...

Cool link. The table just shows if you are using a 5Dmk2, and 70mm lens at f/2.8 and are 6' away (i.e, you are focused at a point 6' out), things will be in focus from 5.82' to 6.19', or 4.4" of depth around the center point. If you stop down the lens to f/8 the area in focus increases to 5.52' to 6.57', or about 12.5" total room. The longer the lens, the tighter things get, and the further away you go, the looser things get. If you have a camera that isn't full frame, things are a bit tighter as well.

If you are good a remembering numbers, just roughly, this table is good for helping one get a feel of what you are working with or against. Same 70mm lens at f/1.4 has about 2" of wiggle room around the point of focus. Come into 3' from your subject, and you have about 1/2" (or 1/4" past your focus point).

Thanks for sharing that. It's a nice table and tool. Almost makes me want a fancy iPhone....

LiquidAir

Here are a few tips:

When shooting at f/2 only one eye will be in focus. Accept that and choose well. If the wrong eye is in focus, the whole shot will appear out of focus.

If done carefully with a longer lens (85mm or 135mm) focus and recompose is not normally a problem. However, you have to be very careful about how you move the camera so it doesn't move forward or backward while recomposing.

The center focus point is more accurate and more reliable than the outer points on most cameras. Test your camera on a fixed target to see which focus points are good enough to handle your fast lenses.

Practice, practice, practice. I need to be shooting nearly every day to be able to reliably hit focus at f/1.4 A week away from my camera and it'll take a few hours of shooting before I get it back.