Picutres out of focus - Lens or my fault?

Quazzap · Aug 3, 2014

Hi,

Most of my pictures are out of focus when I shoot with a wide aperture with my 85mm 1.8 on a 70d.

I focused on the eye with single point AF.
Did I move too much? Or does the lens have front-/backfocus?

f1.8 1/2000 iso 100

thx for your help

Overread · Aug 3, 2014

You can test a lens for front/back focus yourself. All you need is to get a ruler or lined paper or download one of the many free "focusing test charts" online and then set the chart at a 45 degree angle to the lens and focus upon one line with the AF. Then take a series of shots at different apertures and you should be able to see if the camera is focusing forward or behind the AF point (note you should use single point AF for this so that you can define the specific spot to focus upon).

You should also remember that at f1.8 the depth of field is very thin, as a result even minor motions of a body moving back and forth as they stand can cause the focus to slip. It can also mean that whilst you've got one eye in-focus the other eye might not be perfectly in line and thus will slip out of the plane of focus.

Derrel · Aug 3, 2014

The eye on the right side of the photo is in focus!!! See the faint green color fringing on her eyelid on the eye on the left side of the photo? That is longitudinal chromatic aberration, and that green fringing shows that that area is BEHIND the point of focus. (see this 50mm Nikkor lens review for an example).

The image appears too "soft", for whatever reason: cheap filter? dirty rear lens element? to slow a shutter speed? Something is not quite right. My impression is wide-open and hand-held, slow speed.

Braineack · Aug 3, 2014

it was shot at 1/2000 and f/1.8

TamiAz · Aug 3, 2014

Things I try to remember when trying to avoid soft focus... Is my shutter speed high enough, Is my ISO too high (you can have correct focus, but noise will make the picture appear oof), Is my exposure correct, Am I using my center focus points, is my depth of field too shallow ( I like to use the sweet spots on my lenses) and I always use back button focus. Also make sure your using the correct auto focus mode. Oh, make sure your lighting is good!!

astroNikon · Aug 3, 2014

try f/5.6

I know ... it is a "draw" to use the f/1.8 (or f/1.4) just because the lens can do it.
But as mentioned above the shallow Depth Of Field is not a good aperture for portraiture .. I've was doing this many, many times when I first started trying too.

Learn what to use f/1.8 for instead of just using it for any and everything.

Use that Ruler test, or even a long chain link fence. take a photo at f/1.8 at a 30 degree angle and inspect the photo in detail. You can see such a small depth that is in focus. Then superimpose a person there and that person will only have a small part in focus. You need to use a aperture that will put the entire 3-Dimensional depth of the person in focus.

Quazzap · Aug 3, 2014

astroNikon said:
try f/5.6

I know ... it is a "draw" to use the f/1.8 (or f/1.4) just because the lens can do it.
But as mentioned above the shallow Depth Of Field is not a good aperture for portraiture .. I've was doing this many, many times when I first started trying too.
Learn what to use f/1.8 for instead of just using it for any and everything.

Thx, I think this is my mistake. I always say to myself: "I have to use a wide aperture or else I could have gotten a f4 lens..."

frommrstomommy · Aug 3, 2014

I think the problem is the 1.8... try even just 2.8 and you'd probably be perfectly fine for 1 person to be in focus. At 1/2000 you could be dancing while shooting and probably hit your target in focus. lol

Derrel · Aug 3, 2014

Braineack said:
it was shot at 1/2000 and f/1.8

Wow...what a simply pathetic imaging performance for that speed. The file looks extremely soft...just "Uggggh!" bad.. Definitely something amiss here...I would check the lens' rear element and ditch ANY filter that might be on the lens, and also check the lens front. There seems to me to be something wrong here: this image has almost no resolving power. I downloaded the image last night and looked at it full-sized and for an over 5,000-pixel-wide image is seemed unusually low in resolving power. HERE are two crops...showing the areas of best focus. I owned the 85/1.8 EF for seven years--it ought to perform much better than this at f/1.8.

Best focused hair sample:

Best focus, face area:

Something just does not seem quite right here. The resolving abilitiers of that lens ought to be much higher; all we see is a suggestion of hair detail. I'm wondering if the lens is clean, and also am wondering if it might have been knocked hard and something jilted out of place....just seems like it's not resolving ANYTHING clearly, and we can see the focused areas. THe lens just seems to be "suggesting detail": when, even at f/1.8 I'd expect it'd have more crispness at the point of focus. I can tell that the ISO is high, but still, I owned this lens...this doesn't seem to be very good based on what I have shot with the same model lens.

Tinderbox (UK) · Aug 3, 2014

A bit of reading.

?This Lens is Soft??. « Canon Rumors

There is No Such Thing as a Perfect Lens

John.

Quazzap · Aug 3, 2014

Derrel said:
I can tell that the ISO is high, but still, I owned this lens...this doesn't seem to be very good based on what I have shot with the same model lens.

ISO was 100

that1guy · Aug 3, 2014

astroNikon said:
try f/5.6

I know ... it is a "draw" to use the f/1.8 (or f/1.4) just because the lens can do it.
But as mentioned above the shallow Depth Of Field is not a good aperture for portraiture .. I've was doing this many, many times when I first started trying too.

Learn what to use f/1.8 for instead of just using it for any and everything.

Use that Ruler test, or even a long chain link fence. take a photo at f/1.8 at a 30 degree angle and inspect the photo in detail. You can see such a small depth that is in focus. Then superimpose a person there and that person will only have a small part in focus. You need to use a aperture that will put the entire 3-Dimensional depth of the person in focus.

yup! I've done this many times! try bumping up to 2.0-2.8 if you want a slightly larger focus area and a decent bokeh. me personally I won't shoot under a f/4 for something like this. maaaaaybe I'll go to a f/3.5 if I'm feeling froggy.

f/1.8 is so slim you will get maybe an eyelash or two in focus and have everything else blurred good luck! choose wisely!

ruggedshutter · Aug 3, 2014

About how far were you from your subject? Focal depth on an 85mm at 1.8 at 5ft is about .84" or roughly about 3/4 of an inch. At 10ft to your subject you should have a 4 inch depth of field.

astroNikon · Aug 3, 2014

This may be a bit more obvious of "in focus" versus "out of focus" areas of a 85mm f/1.8 @ 1.8
I was doing some focusing tests the other day on one of my bicycles.

You can clearly see the back part of the bicycle is out of focus.
But if you zoom in and down to the tire, you'll find only a small portion of the tire tread in focus. This was taken at about minimum focus distance and the handlebar (which has too much flash rebound from an on camera flash) and the small part of the tire are in focus.