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Canon 50D focus issue
I have a Canon 50D which I got last summer and a Canon18x200mm zoom lens. I have been having an issue with the auto focus on this camera. When pressing the shutter button half way the camera shows me it is focusing based on the red led lights in the view screen, so I am assuming it is focusing on the area shown by the red light. However I am finding that many of my photos are way out of focus. This reached a new high/low at Christmas. I took over 125 photos and only 12 were in focus! I have to wonder if there is an issue with my camera or lens. Has anyone else had similar focus issues?
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Qoman60, welcome to the Digital Grin.
I have to wonder if you were trying to AF indoors in poor light?
What were the lighting conditions?
Do you have an external flash with an AF assist light?
Do you have the images posted with EXIF embedded that we could see some examples of the problem?
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http://nikonic1.smugmug.com/
Like Ziggy said, we need to see exif data and images to make any useful comment. We need to know shutter speeds and apertures at the very least.
That 18-200 zoom lens will be at a real disadvantage indoors after dark without flash.
Moderator of the Technique Forum and Finishing School on Dgrin
I have a 50D and generally shoot situations like that with a Tamron 28-75 f/2.8. Both the body and the lens are fine, but nonetheless, I had some shots at Thanksgiving when I was racked out to 75mm and shooting at f/4.5, when I missed focus enough that it is apparent to me.
I should mention, I always shoot in raw mode. The photos in question were taken in the afternoon and evening so there was sufficient ambient light, imo, several room lights and daylight during the day. I used the built in flash since the old external flash I have that I used with my Digital Rebel does not work with the 50D, but that is another issue. The photos were all of family members, kids and grandkids so I'm hesitant to put them up somewhere on Smugmug without password protecting them. I've made it my policy to not put family photos up without some protection. I'm open to suggestions on how to proceed since I would like try and figure out if I need to send out the 50D while it is still under warranty.
I put 4 photos up converted from the raw files here:
http://topperphoto.smugmug.com/50D-focus/focus-issue/10812468_W6GNe#753957044_pE8kv
pw: 50D-Dgrin<!--EndFragment-->
The first image, child with white shirt and red pants, the pants are in focus as is the child's right hand. It appears that you used the on-camera flash and ambient light is pretty low. The camera probably chose the pants to focus upon because of the low light levels and the pattern on the pants has good contrast.
An external flash with a focus assist light would have been most helpful and I can guarantee a greatly increased keeper rate. A flash modifier and/or off-camera usage of the flash would have created much more interesting light. A larger aperture lens would have improved AF speed and accuracy too but the previous mentioned changes would probably be enough for casual shooting.
In the second image the lady in red in the right side of the scene is in focus, at least the side closest to us is in focus. Again, an external flash with focus assist light would have worked wonders to help with focus. I would also suggest using a single focus point, positioned over the part of the subject you wanted in focus. A smaller aperture should have been chosen in order to get all of the people in focus, if that was important.
In the third image, 2 adults with child, the camera tried to focus on the objects closest to the camera. In this image you can see just how little ambient light there really was in the room. Notice the corner of the room in the upper left. See how dark it is? Your exposure was at 1/60th and the lens was wide open and yet the room light added almost nothing to the exposure. Almost all of the light was from the on camera flash.
In the last image prime focus is in the lower left, on the shirt sleeve and pants. Pretty much all of the preceding comments apply.
I use a Sigma EF 530 DG Super flash in this sort of situation with great success. I typically add either a bounce card device or a scoop modifier and sometimes a flash bracket. The flash is almost always bounced and I almost never use the on camera flash.
This is the flash model that would be appropriate for your camera:
http://www.photo4less.com/pd-productid-2289-k-sigma_169101_sigma_ef_530_dg_super_e_ttl_shoe_mount_flash_for_canon_eos_with_e_ttl_ii_operation.htm
Appropriate Canon flashes include the 430 EX II and 580 EX II.
Flash modifiers:
You can create your own light modifiers (DIY). A couple that I can recommend are:
http://www.fototime.com/inv/908195739C4C0D3
http://abetterbouncecard.com/
Joe Demb also makes an interesting device for sale (reasonable):
http://www.dembflashproducts.com/flipit/
I own a FlipIt product and it works well and is very well made.
A site showing various modifiers in use:
http://www.the-meissners.org/2006-small-albums/2006-flashmod/index.html
Here are some images I shot just before Christmas in probably similar ambient lighting to what you encountered:
Here is an older image, shot inside a house, again similar to your situation but using an external flash and modifier (f13 was the aperture because the image field was pretty deep):
A 100 percent crop from the above image:
Moderator of the Cameras and Accessories forums
One thing I didn't realize was the low level of ambient light in the room. To me there appeared to be plenty of light.
Using the built in flash is only a short term measure till I can purchase an external flash. I have an older Sigma EF 500 DG flash that I use with my Digital Rebel almost always used it as a bounce flash. I got much better results with that setup. However the old Sigma flash doesn't work with the 50D and I will be buying an external flash for the 50D. I will have to struggle with the on camera flash till then.
The single point suggestion I have already changed to the center point, which I used a few days ago when I visited my sister's family. I got very few out of focus photos that way. Only wish I had remembered to do that on Christmas.
Looking at the photos you included with your post, the depth of field seems to be a good deal greater than what I got on my photos. Is that because of the external flash or a smaller f-stop? For me would increasing the iso setting help with depth of field?
I am also thinking about getting a different "walk around " lens for my 50D since the 18x200 is kind of awkward. It works pretty well when taking photos of my grandkids sports games.
Most people are surprised at the low level of light inside their house. If you were to meter the light and shoot with only manual mode and ambient you would quickly see the difference in exposure.
The AF section of a dSLR uses a sensor, similar to the imager itself, and that sensor is indeed sensitive to the ambient light levels.
Our eyes, partially through pupils which automatically open and close according to light values and partly through the use of rods and cones with different sensitivity to light and partly even because of our brain's ability to compensate, does a remarkable job of automatic adjustment and we can think there is much more ambient light than there really is.
Yes, unfortunately Canon changed the pinouts for the hotshoe starting with the 50D. I too also have Sigma EF 500 DG Super flashes which I use with the 40D and earlier camera bodies. You can send in your 500 DG Super flash for a free conversion to be compatible with the 50D, but I'm not sure that the flash would then be compatible with your older camera.
In the mean time, until you get a newer flash, you can shoot in manual mode on your 500 DG Super flash and the AF assist light will still help with AF issues. Manual mode is really not so bad and, as long as you maintain a set distance from the subject and use the zoom to compose, it really is pretty accurate too. I still recommend bounce flash with a fill card for best results as I showed in the samples.
I'm glad you tried it and that it's working for you. See, you're getting used to the new camera.
Yes, you need to use smaller apertures to gain additional DOF, or larger apertures to reduce the DOF, like if you want to isolate the subject. The flexibility of a choice of apertures is a tremendous advantage over P&S cameras that lack those features, but it implies an extra responsibility for the photographer.
Much better recommendations for an indoor, Canon compatible, "event" zoom would include:
Canon EF-S 17-55mm f/2.8 IS USM
Tamron SP AF 17-50mm f/2.8 XR DI-II LD Aspherical (IF)
Sigma 18-50mm f/2.8 EX DC Macro
These also make pretty good "walk-around" zooms.
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I think you will find that indoors flash photography works very nicely if you up the ISO to 400 or more. The flash does not have to work near as hard and you will capture more ambient light as well.
I shoot my Christmas candids at ISO 800-1600 with a 40D in Manual Mode with the flash in ETTL. As long as the images are not under exposed, ISO 1600 with flash indoors in a very nice combination.
This image was shot at ISO 1600 with a 40D with supplemental flash at f2.2 1/100th ISO 2600 135mm focal lenght
Moderator of the Technique Forum and Finishing School on Dgrin
I was looking at the Sigma 17-70mm f2.8-4.5 DC IF lens among the Sigma and Tamron lenses you mentioned. I like the thought of a slightly longer zoom the 70mm would give, even if it is at f4.5.
The Sigma EF 500 DG works great with the D Rebel I still use when I want a bit smaller camera to cart around. The 50D has so many more options and settings it is somewhat overwhelming! I am starting to get a handle on a few of the settings, the rest will take time. It has a learning curve compared to a P&S or even the Digital Rebel series!
Looking at the Sigma EF 530 DG flashes on Amazon, what is the difference between the ST model and the "Super" apart from price?
I have noticed that when I use the auto iso setting on the 50D for indoor flash photos that it often is using iso 320 or 400. I will have to try setting the iso to 400 manually and try that next time. Thanks for that suggestion. That photo link you posted looks great! I can tell you are a much better photographer than I am! But I'm not too old to learn.
If you really want superior indoor performance I suggest a constant aperture zoom of f2.8 or a prime lens with f2 or larger aperture.
The Sigma 17-70mm f2.8-4.5 DC IF is a very nice outdoor zoom, but your camera has an AF point specifically designed for faster performance and more accuracy at f2.8. The zooms that I recommend for you each have that property. In addition, the Canon that I mentioned (Canon EF-S 17-55mm f/2.8 IS USM) has the fastest and most accurate focus motor technology and Image Stabilization to help with camera shake. The Canon will give the best overall performance and the highest keeper return rate of accurate AF. The Tamron SP AF 17-50mm f/2.8 XR DI-II LD Aspherical (IF) is a pretty good alternative at a very reasonable cost.
Here is a link to the appropriate Canon description of the AF sensor and the mention of the f2.8 sensitive AF point:
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=ModelFeaturesTabAct&fcategoryid=139&modelid=17499&pageno=4
The Sigma EF 530 DG ST lacks some of the sophistication that is included on the Super series. In particular the manual mode is more limited, there is no second-curtain sync, and the ST models lack the ability to act as either master or slave in a multi-flash scenario. Also the Super versions have High Speed Sync, allowing faster shutter speeds and use of the flash in sunlight situations. The last 2 features alone, the master-slave capability and high speed sync, are easily worth the minor upgrade costs of the Super over the ST series.
I highly recommend going with the Super series or a genuine Canon 580 EX II. They have the power and the features to carry you into the next level of photographic capabilities and image quality.
All in all, the Sigma 530 DG Super flash and the Tamron zoom lens will give you the best return of keepers for the least amount of money, and give you enough additional features to allow for photographic growth.
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