Focus issues, advice desired. - DPChallenge Forums

Panasonic LUMIX DMC-LX100

10/21/2013 10:28:59 PM · #1

So I've had my DSLR for about 18 months and just started shooting with manual mode this summer. I have a Nikon D5100 and just recently noticed my photos weren't in great focus. Or at least the focus area in auto mode was not where I wanted the focus to be. The default seemed to f/4 when scene called for f/11. This seemed to happen numerous times over the past few days. I rarely shoot with my 18-55 mm kit lens, but I have been using it lately and it seems to be the lens that gives me trouble. My question is would a higher quality lens make a difference, or am I more likely having technical issues? (My worst focus troubles came during shoot on a very gloomy and windy day, and I neglected to setup my tripod. However my Nikon V1 with the worked beautifully.) Thanks.

mpeters

Canon EOS-5D

Canon EF 50mm f/1.8 II

10/21/2013 10:42:42 PM · #2

Can you post a sample image along with exposure data?

spiritualspatula

Nikon AF-S NIKKOR 24-70mm f/2.8G ED

10/21/2013 10:55:14 PM · #3

I don't follow specifically why you are referencing your aperture when determining if there was a missed focus or not. Are you referring to your exposure being off, especially since you discussed recently using manual mode?

bohemka

Nikon D700

Sigma 12-24mm f/4.5-5.6 EX Aspherical DG HSM for Nikon

10/21/2013 11:04:14 PM · #4

I think you mean metering, not focus?

Sony 24-70mm F4 Vario-Tessar T* FE OSS

10/21/2013 11:07:31 PM · #5

A very confusing post.

Bear_Music

Samsung Galaxy S24 Ultra

10/21/2013 11:17:18 PM · #6

Assuming you ARE having focus issues, and since you say the issues were especially bad on a gloomy, windy day: be aware that autofocus on a dSLR works by detecting contrast, and the slower lenses (not so large a maximum aperture) like your kit lens exacerbate the problem by delivering much less light to the sensor and by having less native contrast than more expensive glass.

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

10/22/2013 10:31:12 PM · #7

Sorry to be confusing. I'm just starting to get terminology down, but it's a lot to keep track of and I'm not sure it's right in my brain yet. I had mentioned aperture because I wondered if depth of field was too shallow and that was why I was not seeing anything in focus.)

f/3.5
1/200 sec
ISO-200
18 mm

f/5.6
1/125 sec
ISO-400, 55 mm

BrennanOB

Canon EOS-1D Mark II

10/22/2013 10:36:33 PM · #8

A great way to check your focus on a lens is to shoot a 20 foot tape at a low angle at various f stops. Put your camera on a tripod and center the focus on 8 feet, and try. You will quickly see where your focus point really is.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

10/22/2013 10:48:33 PM · #9

Thanks. I will try that.

GeneralE

Canon PowerShot S3 IS

10/22/2013 11:10:40 PM · #10

Originally posted by BrennanOB:

Is the zero point of the tape at the front of the lens or the sensor plane?

Bear_Music

Samsung Galaxy S24 Ultra

Sony 24-70mm F4 Vario-Tessar T* FE OSS

10/22/2013 11:52:46 PM · #11

Originally posted by GeneralE:

Originally posted by BrennanOB:
A great way to check your focus on a lens is to shoot a 20 foot tape at a low angle at various f stops. Put your camera on a tripod and center the focus on 8 feet, and try. You will quickly see where your focus point really is.

Is the zero point of the tape at the front of the lens or the sensor plane?

It doesn't matter for this.

MelonMusketeer

Panasonic LUMIX DMC-LX100

Nikon MF 50mm f/1.4

10/22/2013 11:54:40 PM · #12

Make sure that AF is turned on in both the camera and the lens if you want to use autofocus. Sometimes I forget to switch a lens back to AF after shooting manual focus.

Another item to check is the viewfinder diopter adjustment. It's a little adjustment wheel right alongside the viewfinder on the right side. To set that accurately, set the camera on the tripod, then use AF on something that looks like it should have a definite and not confusing focal point, like a single object near the camera and far from it's background. When the camera gets focus, switch the camera off, making sure you don't touch the focusing ring on the lens, then look in the viewfinder and turn the wheel until you can see the object the clearest.

If the 5100 has live view, you can use the tripod setup as above, and live view, then zoom in the same way you zoom in on playback, to see if focus is correct.

Also, have a close look at the lens with a good bright light, and look for smears or dust on it, esp the rear element.

When hand held shooting. Make sure VR button on the side of the lens is in the on position.

I have used the 18-55 VR, 18-70, and the 18-105 VR, and the VR makes a huge difference, esp in low light. Both the 18-70 and 18-105 appear to be much sharper than the 18-55 that I tried while sharing the 18-105 with a friend.

In reading your original post, I notice you are talking about aperture not being what you want. If you have the camera in "Manual" mode, then you have to choose your desired aperture, shutter speed, and iso. The camera does not auto adjust any of those in the "Manual" mode.

Message edited by author 2013-10-23 00:41:53.

spiritualspatula

Nikon AF-S NIKKOR 24-70mm f/2.8G ED

10/28/2013 02:44:01 AM · #13

Any luck shooting a tape? These posted examples are unacceptably soft throughout the entire scene. Some shots from a tripod or using the timer on some sort of support would help illustrate what might be causing this. Are you waiting for the lens to acquire focus being actuating your shutter? Do you have your camera set for focus priority or release priority?

Giles

Canon EOS-5D Mark III

Canon EF 24-70mm f/2.8L USM

10/28/2013 03:24:11 AM · #14

The camera will always focus at quickest aperture it can, you only get in trouble with the canon bodies on lens above f8 some of the 1 bodies will go a bit higher, then why you have a depth of field preview button.

It sounds more like you've got blurry images from your slower shutter than autofocus

It's a myth that most pros shoot manual day to day, all the ones I know and me included shoot av mode in auto ISO

Only shoot manual with strobes or tricky situations

Do some tests on a tripod or boost your ISO up and use fastest aperture lens you have

aliqui

Nikon D300s

Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II

10/28/2013 11:34:59 AM · #15

Originally posted by MelonMusketeer:

When hand held shooting. Make sure VR button on the side of the lens is in the on position.

I wanted to accent a line from

MelonMusketeer's fine post. The VR button should be used when hand held shooting, not when on a tripod. If you use VR in conjunction with the tripod it screws with the gizmos and do-dads and you end up with a blurry photo.

Tiny

Apple iPad mini 4

10/28/2013 12:41:51 PM · #16

I think you are confused,or at least i am. Are you shooting Manual FOCUS or Manual EXPOSURE ?

I would forget about manual exposure for the moment and get to know the rest real well.

As Giles says you don't really need to bother with that.

10/28/2013 01:25:24 PM · #17

Ok..

Reading through this I'm starting to wonder if there's not something really wrong with your lens.
The thing that really worries me is the fact that all of the photos have a nearly consistent blur, and it's gaussian (or nearly gaussian) - in other words, it's uniform blur, and it seems that there may be two images, one in focus, and the other out of focus.

This is what I would expect if the lens is physically damaged, with a single element out of place.

Try this, exactly this, and post the result please.

Find a place where you can shoot down street in front of a set of buildings, or something of that sort where there are many detailed objects at a continuously increasing distance from the camera.
Set your camera on a wall, or on a tripod - make sure VR is disengaged on the lens.
Put your drive mode into continuous (shoots while you hold down the button), or use a remote release (to avoid any possible shake)
Focus on something at about 15 feet away
Shoot 5-10 shots.

Pick the best two, and post them here.

--

What this should achieve is to take the human out of the equation, and can give us an idea of whether or not ANYTHING is EVER in focus. From the test shots you posted, I think it's likely we might find that it simply never focuses.

Another test - can you borrow another lens to try for a few minutes? Any camera store should be able to do this, or maybe a near-by DPC'er can help?

10/28/2013 07:52:17 PM · #18

The tape measure exercise was very enlightening. At f/5.6 it was not in focus, but at f/11 or f/13 the numbers could easily be read. My camera seems to choose f/5.6 as default a lot.

I stopped on my way home from work and took repeated shots of downtown buildings. These were the two best shots, about three of 10 shots were slightly blurry. VR was off. Camera was on a tripod. It was overcast about an hour before dusk. My remote release was at home so I was using the camera shutter release button.)

At the mention of the possibility of a lens problem, I suddenly remembered 'The incident of the lens at the camera shop.' whereby this lens was dropped on the floor during a few moments of confusion between the shop guy and me. (Apologies for forgetfulness. I am your typical absent-minded scientist, one who has on one mortifying occasion gone shopping with pants on inside out.) This mental defect means that after the shop guy and I did a bit of quick testing and decided the lens was probably okay, I forgot all about it.

I thought the building shop photos were decently in focus, but perhaps not? (Both photos are 55 mm, f/5.6, 1/60 sec. ISO-400 VR off. Auto focus on.)

Closest camera shop is 90 miles away. I may have an opportunity to get there this week, but it depends on how early I can escape work on Thursday. I will work on getting a lens to compare to.

Thanks for all of your ideas.

10/28/2013 08:30:21 PM · #19

I'll say it now without hesitation.

That lens is messed up. The drop probably knocked an element loose. Move it around carefully and see if you can hear anything loose?

And FYI - the two images you posted are identical. :D

Message edited by author 2013-10-28 20:30:46.

MelonMusketeer

Nikon MF 50mm f/1.4

10/28/2013 08:33:10 PM · #20

One other thing comes to mind about this problem. If you are using any kind of filter on the lens, try shooting with it off the lens, bare lens, and see if things change. Some filters are a lot better than others, and a bad one can cause the kind of blur you are seeing in the photos. I have banished a couple of cheap ones to just being glass lens caps for that reason.

jomari

Nikon AF-S DX 18-105 f/3.5-5.6 ED VR

10/28/2013 08:34:58 PM · #21

Originally posted by Cory:

They might be identical as far as focus goes but they are not the same shot. I can see the heads in the car move a little, as does the frame itself.

10/28/2013 08:36:33 PM · #22

Originally posted by jomari:

Originally posted by Cory:
I'll say it now without hesitation.

That lens is messed up. The drop probably knocked an element loose. Move it around carefully and see if you can hear anything loose?

And FYI - the two images you posted are identical. :D

They might be identical as far as focus goes but they are not the same shot. I can see the heads in the car move a little, as does the frame itself.

Fair enough.. I was mostly talking about the settings on the camera though - f/5.6 ISO400 1/60... :D - It would be interesting to see what a shot with a narrower aperture would do.

MelonMusketeer

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

Nikon MF 50mm f/1.4

10/29/2013 09:48:38 AM · #23

The two were shot in fairly low light and wide aperture. The focus seems to be on the car in the foreground, and so the background is out of focus due to the wide aperture.
Unless the tripod is a pretty solid one, you will have camera shake by hand triggering at 1/60 sec. For test shooting self timer or remote would be useful to help with that.
Check to see if "sharpening" is turned off in the camera too. In a Nikon, it's in the "Picture Control" menu.
The 18-55 is not a very rugged lens, so the drop in the store may be the whole problem.
See if you can borrow another lens and compare the results. That would eliminate a lot of variables about shooting technique.

BrennanOB

Canon EOS-1D Mark II

10/29/2013 12:28:33 PM · #24

Shooting everyday subject matter is a tough way to diagnose a focal issue.

The tape test will tell you if you are back of forward focused, and posting your test shots will help us try to diagnose the issue.

Then there is the question of if the lens is sharp across the image. The easiest way for this is to set the camera up on a tripod square to a wall and shoot the wall. Print out 5 of these test charts and tape them to the wall in the corners of the image. Shoot in manual mode, from wide open to stopped down all the way, and repeat the test at several places in the zoom range, moving the test charts out to the corners as you zoom in. I would bet that your results will show that your elements have rearranged themselves so the lens can no longer focus in a plane, but is skewed.