Help me test my lens sharpness

[eric-holmes]

I took four different pictures with my 50 1.8 to find the sharpness. I used aperture mode and let the camera determine the shutter. No PP was done. These are SOOC JPEG quality.

Tripod and remote release was used.

f/8 s1/8

f/6.3 s1/13

f/4 s1/40

f/2.8 s1/80

 

[D-B-J]

whatever your taking pics of.. it seems oof?

 

[D-B-J]

but if they are crops, the first one seems to be the sharpest.

 

[tsaraleksi]

What, exactly, are you trying to figure out?

 

[photonewbie86]

What are you taking pictures of wood?

 

[chuckinsocal]

Since we have no idea of what your subject is supposed to look like, we have no idea if it's off or not.

Try taking photos of something with high contrast with lines that we know are supposed to be sharp and straight. Perhaps a white box with black lettering from Office Depot or something like that.

 

[usayit]

Lay down measuring tape along the floor. Setup a tripod with the camera pointing down at a 45 (or less) angle focused on a number/mark on the measuring tape. Make sure you get focus confirmation and use a remote. You should have good light and use the lowest ISO setting. Take a photo.

Examine the photo... is the number you are focused at the sharpest. Is it the number or marks behind or in front of the intended focused number/mark sharpest?

 

[Derrel]

The 1/8 to 1/30 range your smaller-aperture shots are made at is kind of a dangerous zone for mirror slap and shutter vibration. On many lighter-weight camera bodies and lighter-duty tripod heads, there can,at times, be some vibration patterns that make exposures in the 1/8 to 1/30 second range prone to softness from the slap of the mirror going up, then the first shutter curtain racing across the film plane and exposing the film/sensor, and then the second shutter curtain closing to end the exposure.

On a danger zone shutter speed, like say 1/8 second, the mirror creates slap as it swings up...then the first curtain thunks open...and so there are two (potential) vibration-causing effects, which are recorded in a brief exposure that takes as long to make as it takes for the vibrations to quell; longer exposures, like 4 to 6 seconds can actually appear sharper and less-affected by vibration than those in the 1/4 to 1/30 second range. One solution is to use a flash exposure to test sharpness...the flash duration is very,very brief, and guarantees there will not be sharpness lost due to camera vibration.

That faded wood test target is not the best target....I'd rather see a page ripped from a magazine taped to a wall or something like that. The test target looks best in the first shot. Focusing accuracy is huge on these kinds of tests. I see that the shot done at f/6.3 and 1/13 second looks very slightly less-sharp than the one done at f/8 and 1/8 second; that could be due to any number of factors--mirror slap, slight camera vibration, or a very minute focusing error, or a bit of focus shift on the lens; many lenses will shift their point of focus a bit between wide-open and the shooting aperture.

These kinds of tests demand really,really careful control if the tests are to be 100 percent trustworthy. Can you use your camera's Live View, to determine if there is some focus shift by focusing with the lens wide-open, and shooting a series of test shots at one specific aperture, and then doing another series of shots focusing with the lens stopped down to the shooting aperture? (Does your body even offer Live View?)

 

[ghpham]

Lay down measuring tape along the floor. Setup a tripod with the camera pointing down at a 45 (or less) angle focused on a number/mark on the measuring tape. Make sure you get focus confirmation and use a remote. You should have good light and use the lowest ISO setting. Take a photo.

Examine the photo... is the number you are focused at the sharpest. Is it the number or marks behind or in front of the intended focused number/mark sharpest?

I believe this is use to test...back focus? He just wanted to test lens sharpness?

 

[fokker]

Lay down measuring tape along the floor. Setup a tripod with the camera pointing down at a 45 (or less) angle focused on a number/mark on the measuring tape. Make sure you get focus confirmation and use a remote. You should have good light and use the lowest ISO setting. Take a photo.

Examine the photo... is the number you are focused at the sharpest. Is it the number or marks behind or in front of the intended focused number/mark sharpest?

I believe this is use to test...back focus? He just wanted to test lens sharpness?

Can't see why it wouldn't be a good way to test sharpness too...

 

[Johnboy2978]

Here's a downloadable focus chart:
Nikon D70 Focus Chart

 

[Overread22]

Lay down measuring tape along the floor. Setup a tripod with the camera pointing down at a 45 (or less) angle focused on a number/mark on the measuring tape. Make sure you get focus confirmation and use a remote. You should have good light and use the lowest ISO setting. Take a photo.

Examine the photo... is the number you are focused at the sharpest. Is it the number or marks behind or in front of the intended focused number/mark sharpest?

I believe this is use to test...back focus? He just wanted to test lens sharpness?

Can't see why it wouldn't be a good way to test sharpness too...

Another bonus that I have found when testing my own lenses is that shooting at an angle means that any accidental missfocusing does not affect ones ability to judge the sharpness - whilst shooting flat on one can sometimes wonder if the focus has been a tiny bit out - a very easy thing to do with large apertures (Eg f2.8) or in my case where I was testing macro lenses at high magnifications.

 

[Early]

To tell you the truth, none of these come close to being sharp. Refocus and try again.

 

[Soocom1]

Ime with Early on this. if your shooting manual, check your diopter adjustment for any focus issues. usayit has a good idea, and the focus chart is a good idea too.

If your useing atomatic focus, take head of the distance your shooting. Most standard lenses are a bit nearsighted, and cannot focus under 1 foot (correct me if I am wrong on that distance.)