I am editing some photo's I took of my wife. (I will probably post them later if I am happy with them)

To shoot these photo's I used my 50mm 1.8 Wide open. Its really been my first test run with this lens since I got it...


This lens is supposed to be like - Spot on razor sharp focus. But all of the photographs seems out of focus. I shot all of them at 1.8

So my questions about shooting this wide open is...

Is it just such a narrow DOF that I couldn't possibly get her whole face into focus? should I shoot at a higher F stop for a Head and shoulder shot?

This is the only lens I have that opens that wide - so I'm not sure if this is a normal result.

I'm including one of the shots - Unedited, no WB adjustment or cropping. Tell me what you think of the focus.

Did I just miss?

Am I crazy and her face is in focus?

What happened?

Shot at f/2.5 50mm 1/60th


P.S. I realise I said I shot them all at 1.8 and this one is at 2.5 but humor me

Ian,

We should talk.

I can explain it for you.

This is a common "user error" and nothing to worry about.

More later.

Lets do some calculations.
Find a good depth of field (DOF) calculator (google knows where)

Input the values -
-f stop,
-lens focal length and camera (so the crop factor can be figured out.)
-distance to subject.

The calculator will tell you:
-the total DOF
-the DOF in front of the focus point
-the DOF behind the focus point
Then you can look at your model and consider stuff like:
-how far is it from her eye (usual focus point) to
--her other eye
--her ear
--the hair behind her far eye.

After calculating all of the above you may decide:

- to choose a pose where both eyes are the same distance from the camera or almost the same to keep them sharp.

- to choose to keep the necklace blurred or sharp.


There lots to decide. A look at the calculator will be a good start.

Ian Bower wrote:Is it just such a narrow DOF that I couldn't possibly get her whole face into focus? should I shoot at a higher F stop for a Head and shoulder shot?
This is probably the biggest issue. At f/1.8, the DoF is very narrow requiring you to shoot straight on to get the whole face in focus. If the person is tilting their head, you'll see the effects of a narrow DoF very easily.

Jim Rickards wrote:
Lets do some calculations.
Find a good depth of field (DOF) calculator (google knows where)

Input the values -
-f stop,
-lens focal length and camera (so the crop factor can be figured out.)
-distance to subject.

The calculator will tell you:
-the total DOF
-the DOF in front of the focus point
-the DOF behind the focus point
Then you can look at your model and consider stuff like:
-how far is it from her eye (usual focus point) to
--her other eye
--her ear
--the hair behind her far eye.

After calculating all of the above you may decide:

- to choose a pose where both eyes are the same distance from the camera or almost the same to keep them sharp.

- to choose to keep the necklace blurred or sharp.


There lots to decide. A look at the calculator will be a good start.


Wow! I never even knew such a thing existed. I will check it out. I am sure that it will at least give me an idea of what kind of range I am talking about.

thanks!

kakomu wrote:
Ian Bower wrote:Is it just such a narrow DOF that I couldn't possibly get her whole face into focus? should I shoot at a higher F stop for a Head and shoulder shot?
This is probably the biggest issue. At f/1.8, the DoF is very narrow requiring you to shoot straight on to get the whole face in focus. If the person is tilting their head, you'll see the effects of a narrow DoF very easily.

thanks! I guess I will try experimenting at higher F stops.

A simple rule of thumb is your depth of field will be 1/3 in front of your focus point and 2/3 behind it. The distance will increase with smaller apetures, but the ratio of 1/3 in front and 2/3 behind should remain the same.

I think that the problem lies more in the fact that it was shot at 1/60th, and not the f/2.5 aperture.
I will let Steady say what he has to say though, because I may be wrong, and look like a fewl.

Canon 50/1.8? I don't think that lens has a good reputation for sharpness.

spada wrote:
I think that the problem lies more in the fact that it was shot at 1/60th, and not the f/2.5 aperture.
I will let Steady say what he has to say though, because I may be wrong, and look like a fewl.



Not to worry. I have been known to say something fewlish myself.

The slow shutter speed could certainly be part of the "soft" look. Hand shake....

jfinite wrote:
Canon 50/1.8? I don't think that lens has a good reputation for sharpness.


Au contraire, mon ami!

That model /lens is known for being sharp....at the right APERTURE and use.

Of course there may be variations....but it is known as a sharp lens for less than $100.

Highly recommended for a start or a pocket.

One more thought that may add something here: Where was the focal point? When you focused and re-composed, where did you focus? Her hair looks slightly more in focus to me than her face. Also, if you did in fact use her face to focus, there is a chance your copy of that lens might be slightly front-focusing. Some testing with charts and focus points could help with that. (And tripod) Less likely, perhaps, than user error, but another thought.

Jeremy

jfinite wrote:
Canon 50/1.8? I don't think that lens has a good reputation for sharpness.


Nikon

Jeremy1981 wrote:
One more thought that may add something here: Where was the focal point? When you focused and re-composed, where did you focus? Her hair looks slightly more in focus to me than her face. Also, if you did in fact use her face to focus, there is a chance your copy of that lens might be slightly front-focusing. Some testing with charts and focus points could help with that. (And tripod) Less likely, perhaps, than user error, but another thought.

Jeremy

Jeremy's comments pretty much some up my thoughts as well.

The more information you can provide, the better. We need to know things like, were you using center focus point only, or multiple focus points? One shot focus, or something else? If you were using center focus point then you must have focused and recomposed...but we can only guess how you shot the picture.

There are some pretty simple ways you can test your camera/lens for front or back focus, but first more information would be helpful.

Mark

Jeremy1981 wrote:
One more thought that may add something here: Where was the focal point? When you focused and re-composed, where did you focus? Her hair looks slightly more in focus to me than her face. Also, if you did in fact use her face to focus, there is a chance your copy of that lens might be slightly front-focusing. Some testing with charts and focus points could help with that. (And tripod) Less likely, perhaps, than user error, but another thought.

Jeremy



I was trying to focus on her face. I think you are right about the hair. it seems like the little lock of hair over her eye, and part of her eye are in focus.

Ian Bower wrote:
jfinite wrote:
Canon 50/1.8? I don't think that lens has a good reputation for sharpness.

Nikon

Hmm, you might want to take a look at Olympus and the 50/f2.

^ comparing a $500 macro lens to a $100 plastic-o?

The 50/1.8 is supposed to be sharp wide open. Her left eye is much more in focus. You probably have a little camera shake issue, but more DOF issue. Unless this was heavily cropped, you're pretty close so your DOF is going to be very thin.

I've come to the conclusion shooting with the 50/1.8 wide open that

1) the calculators don't lie about how shallow the depth of field is :-)
2) the picture doesn't lie about how shaky my hand is
3) I inevitably underestimate my ability to move the camera sometime between focusing and shooting, thus potentially exacerbating 1) above

On the odd occasion that I nail a shot with that lens wide open (or close to), I'm always happy; I liken shooting with that lens to the way I play golf...

I'd say the focus is pretty good and the picture should sharpen up quite nicely.

If you are shooting with Nikon Dxx your crop ratio is 1.5. The rule of thumb says your maximum shutter speed should be 1/75 s [calculated from 1/(50*1.5)s].

The image is a little over-exposed. With faster shutter speed you would have nailed the lighting and produced a sharp shot.

2 issues:

1. The 50 1.8 is NOT super sharp at 2.5. Stop down to about 3.5 for better sharpness. A 2 pass sharpening will help this. (A: high radius, low amount for better midtone contrast...the 1.8 at 2.5 has some halation that destroys midtone contrast (which helps with the appearance of sharpness and "pop". B: regular sharpening)

2. at 2.5 the DOF is too thin to get both eyes in focus from the side a this distance. 3.5 would fix it I bet.

3. (yes i know i said 2 issues) possibly a bit front focused.




Experiment!!!