1/08/2013

Reader Question: Why Are My Photos Out of Focus?



I'm answering another blog readers question today - a common problem that probably happened to every single one of us all when we got our first DSLR!

"I found your blog about a week ago in anticipation of upgrading to my first dslr. I really enjoy your blog. After learning everything I could in a week pouring over photography sites I thought I was ready to take pics with my new Canon T3i (just received last night). I only have 2 lenses right now: 18-55mm kit lens and the 50mm f/1.8 (per your advice!). I took about 40 pictures last night of 4 different subjects (3 children and 1 practice object) using both lenses. The results are terrible (all subjects are out of focus when zooming in on the pics). I was able to get the blurred background effect (bokeh?). Below is some of the info of the shots taken. I only used AV mode (as recommended) and tried different Apertures and even ISOs. Also, no flash was used (part of the reason for upgrading to a dslr) so I adjusted a couple light settings for the 50mm to get enough light. One interesting note was when using the 50mm and trying live view rather than the eye piece on my last attempt, my subject was in sharp focus



Kit lens:
Aperture: 5.6 (first time out of box)
ISO: 3200 (Camera chose this)
Shutter Speed: 1/15 (Camera chose this)
AWB
Spot Metering
Distance from subject: Approx. 4-6ft

50mm lens:
Aperture: 2.0-2.5
ISO: 200, 400, 800 (I kept changing this this)
Shutter Speed: 1/8 - 0"4? (Camera chose this)
AWB
Spot Metering
Distance from subject: Approx. 2-4ft

Any ideas?

This is such an incredibly common problem for people have when they get their hands on their first DSLR that I thought I would tackle this on the blog today for those readers who are new to photography.

The problem is instantly clear to me - in every single one of the settings you have given me your shutter speed is far too low.  Many people think that their  DSLR camera will pick the correct shutter speed for the job - and a lot of the time it does - unfortunately, sometimes it also gets it woefully wrong, as it has in this case.  This is particularly true if you are shooting indoors or in low light. 

To help you understand this a bit better, I'll give you a little info on how your camera works.  In basic terms, your camera needs enough light to reach the sensor to capture the image. If there is not enough light (and you are shooting on automatic or aperture priority without flash) your camera will slow down the shutter speed to allow more light to reach the sensor. Unfortunately,  slower shutter speeds means blurry photos! If your shutter speed is very slow, even the slight movement of your hand pressing the shutter will be enough to give you a blurred image even if your subject is stationary - in your case, the shutter speeds above were too slow even for you to get a sharp handheld image most of the time (You must have lucked out the last one!)  If your child was also moving it will have been even worse.  The more movement there is from your subject, the higher the shutter speed you need. 

To start you off, here's what you need to do:

1) Get out of Auto and use AV (Aperture Priority) 
2) Select your Aperture. Start with around F2.8 or F3.6 to begin with. 
3) Select your ISO. If you are indoors start at ISO800, if you are outdoors start at ISO200. 
4) The camera will select a shutter speed for you.  Look at the list below and chooses the activity that best matches what you are trying to photograph, then compare what the shutter speed I have suggested to the shutter speed that the camera selected. 
5) If the number is smaller than the number I suggested, then increase your ISO to a higher number (e.g ISO1600 for indoors or ISO400 if outdoors.) Keep doing this until you get a shutter speed that you need! 
6) If the shutter speed is much higher than I have suggested, move down the ISO numbers until reaching the shutter speed that you need. (it's better to keep your ISO down if you can) 
7) You can also play with your Aperture to let in more light - the reason I am suggesting F2.8 or F3.6 is that it's a good compromise between letting in enough light and having a reasonable depth of field. You can choose a lower number which lets in more light (and therefore will also increase your shutter speed) instead of increasing your ISO if you prefer. 

Suggested Shutter Speeds 
Stationary Subject: 1/80 Minimum  
Child Sitting: 1/125 Minimum 
Moderate Movement: 1/250 Minimum 
Fast Movement: 1/500 Minimum 

This is an extremely basic introduction just to get you going, I would suggest that you read the following articles to get a better understanding of it all. 


Hope this helps! 









8 comments:

Anonymous said...

Thanks for the tips...I'll try increasing my ISO since I can't change the shutter speed in AV mode (although ISO was 3200 with the 18-55mm kit lens and I couldn't decrease the aperture due to being zoomed in for a close up). I have read all your articles already but as with anything it takes practice! I tried going full Manual but only got black pictures...definitely need more practice!

One more thing I noticed today was that I was using AF and didn't know about changing the focal points so even though I thought I was focusing on the subject's eyes, it seems like the camera ended up focusing on other things (i.e. hair on top of head, teddy bear in arms, etc). I'm going to try it with only a single point selected and see if that helps!

p.s. Love your blog!!

Ticky Tab said...

As always, your blogs are perfect!
I have few pictures taken with Canon T3i 50mm 1.8
All my knowledge in photography has been tested each time.. and will be doing same in the future.

https://plus.google.com/photos/101810313484422579829/albums/5828497524664029217?authkey=COj-mb3hq8vK_wE

Feedback/suggestions are very helpful to all in this blog roll. Thanks!

Tasha Meyer said...

I have a question, when shooting in AV mode the camera decides the shutter speed. You can increase the ISO, but that adds more noise to the photograph. Since you can't change the shutter speed in AV and my camera seems to be picking really low shutter speeds would it be better to shoot in full Manuel? Or what is the advantage to shooting in AV if it keeps doing this? Thanks and sorry if I am missing something obvious here! I really love how you explain things!

Audrey said...

Hi Tasha, shooting in manual gives you more control, but essentially you are going to end up with the same numbers. In other words if you want a shutter speed on 1/250 say, and you want to use af2.8 aperture for the depth of field you want, you'll need to choose an ISO that allows you to give that. If that is higher than you want to use then you have the option of slowing your shutter speed, or opening up your aperture. It's the same choices whether in manual or AV. The difference with AV is once you have set your camera roughly where you are meant to be for correct exposure, it will adjust for changing light conditions. Full manual gives you the most overall control, but I don't recommend it until you ave a good grasp of the aperture you need for a shot, and the shutter speed - thie way I mentioned above really is just to begin with as it helps you see the relationship between the three and get a good grasp of what you're likely to need in different situations, so that when you switch to manual you have a good idea of numbers to dial in. Hope this answered your question!

Tasha Meyer said...

It does, it's just a matter of lots of practice now. Slightly OT, but if you shoot a photo in 1600 ISO can you still blow it up to an 8x10 or will it be too grainy? I'm just worried about setting it at a higher ISO and not being able to print anything.The lighting in my house is horrible. Thanks!

Audrey said...

I think it would be fine at that size. One thing I do is turn noisy images into black and white - for some reason the grain looks more better, more like it's meant to be there.....maybe that's just personal preference though but see what you think!

Anonymous said...

Good news....it worked!!! Well my shutter speed still wouldn't reach the recommended speeds even at 3200 ISO in AV Mode (probably due to poor lighting?)....but I got a few GREAT shots on my 2nd try at using my 1st DSLR! I will email you one with the details Audrey in case there are any more specific pointers that can be made from seeing the results. Also, I realized I definitely need a tripod for indoor shots due to the high ISO levels required(my hand just doesn't seem that steady).

Details from one of the pics:
50mm f/1.8 lens
AV Mode
Aperture: f/2.8
ISO: 1600
Shutter Speed: 1/50 (Camera chose this)
Exposure bias: +1 step (to brighten things up)
AF: Auto Focus on but only 1 point selected and focused on closest eye
Flash: No flash

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