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Why are these photos blurry?


I have a Canon Rebel T3i. I have taken a number of group photos w/tripod, w/o tripod, w/flash, w/o flash, various apertures, many on automatic mode. All on autofocus. All of them come out fuzzy, especially the people on the ends. The attached might look ok small on this web page, but if you download it and look at it 100% you will see what I mean. I have two T3i cameras and they both yield the same results. I would probably get a better photo with a phone. Any ideas?




@dtrachtman wrote:

The lens is a Canon EF 18-135. Photos taken at shutter speeds from 1/8 to 1/250 and f3.5 - f9.0. Why does the fact that the ends are blurrier imply this is a poor quality lense? What type of lens should I buy? thanks

The 18-135 has a pretty good reputation, but for this purpose you'd be using it at the wide end. Lenses with a long zoom range (and yours is fairly long) tend to be sharper in the middle of their range than at the ends. The ends of your group are blurry because sharpness falls off as the subject gets farther from the center of the lens. More expensive lenses tend to do a better job of minimizing that effect. 1/8 of a second will usually work if you're using a tripod, but it's too slow for this kind of picture, because the subjects will move around. I wouldn't use anything slower than 1/160 for group pictures, the only exception being when a flash is providing most of the light. For group pictures I normally use the Canon 17-55mm f/2.8 IS on a 7D body. That lens is very good and cheaper than it used to be. Whether that lens would solve your problem, I don't know. Maybe you could rent or borrow one and try it. Note that although you'd still be using it at the wide end, it doesn't have to worry about being sharp at 135 mm.

Philadelphia, Pennsylvania USA

View solution in original post


Hello all again,

I wanted to update this topic and see if anyone had any other ideas. I have now tried the following and none have solved the problem of the people on the sides of my group shots being blurry:

-Made sure the camera focuses on the faces in the middle in both auto mode and manual spot mode

-Used two identical Canon t3i cameras

-Tried smaller apertures and faster shutters

-Used a tripod

-Purchased and tried

a Tokina 11-16 lens

-Purchased and tried a powerful flash


I havent tried raw yet although I doubt it would make much of a difference in this case.


Below are a couple more examples. I had to crop one to get under the 5meg max.






You are getting an effect called "chromatic aberration" (often abbreviated "CA").  This can be fixed in software if you have the right software.


When light passes through glass at an angle (like a prism) the light bends (it's why a straw appears to bend if you look at it in a glass of water even though you know the straw is straight).   But blue light (shorter wavelength light) bends more than red light (long wavelength light).   


The edge of a single element of convex lens works like a prism and does this to the light.  The lens maker uses additional lens elements to try to correct for the problem.  It's possible to mostly correct it -- but almost impossible to be perfect.  Some high end glass does a much better job than entry-priced lenses.


Look at the woman on the far left on the bottom photo.  She's got a black jacket and a brooch.  Look at the left edge of that brooch and you'll notice it has a blue fringe.  Look at the right side of the brooch and you'll notice a red fringe.   That's the CA effect.  It's softening or blurring the quality of your image. 


Due to the way CA works, you'll find no effect in the center optical axis of the lens, but you will see the effect around the edges.  


Computer software can separate the color channels, then squeeze or stretch the channels so that they all exactly fit on each other, then recombine.


If you decide to search for a different/better lens, I would recommend renting so that you can evaluate the quality and make sure you've find a lens that meets your needs... then go buy the lens you like the best. 


Tim Campbell
5D III, 5D IV, 60Da

Hi TCampbell,

Thanks for the suggestion. If it were just CA, then if I looked at just one color channel in Photoshop, it should be sharp, right? It is maybe a little better, but still blurry.



Opanda EXIF software tells me that your sample shot was done with T3i and 18-135mm II lens at ISO 400, 1/60 shutter speed, f4 aperture with the lens zoomed to its widest 18mm and the camera doing all the exposure settings in Program mode. Also, the flash fired.


All the recommendations about focusing technique are well and good. I'd also use a single AF point, manually selected. Probably the center one. Also I'd use One Shot as the most accurate of the viewfinder-based AF focusing modes. Alternatively, Live View focus could have been used, which is slower but can be even more accurate. It also can help with manual focus, if you do that instead, because you can magnify the Live View image up to 10X on most cameras that have it.


In this case, I'd take several shots, refocusing each one. The reason is the lighting, which appears to be common fluorescent, which is notorious for "messing with" focus and metering accuracy. The reason is that fluorescent lamps cycle on and off at a high rate... 120 Hz in the US, 100 Hz in some othre parts of the world. This is so fast the human eye doesn't notice. But our cameras can and do see it... and can be fooled by it.


However I think the main problem is that your are using an f4 aperture. Lenses are typically not at their best and sharpest at or very near their largest aperture. Stop down to f5.6 or f8 and I think you'll see a lot of improvement. To do so, you'll have to get out of Program mode and use Av or aperture value exposure mode instead. This still gives you the same auto exposure and flash performance, but will allow you to select the aperture, after which the camera will automatically set the appropriate shutter speed. You may need to set a higher ISO to get adequate shutter speed.


Stopping the lens down also would give you more depth of field to work with. That can be very important because another concern is "field curvature". When your subjects are in a straight line and you focus on the one in the very middle, chances are that natural lens field curvature effects toward the edges will cause subjects there to be softer. This is more pronounced the wider angle the lens is... Ideally you would instead line up the people in a slight arc, where the ones on either end are a little closer to you. However, you'd be guessing or basing your posing on experience... because it's hard to see in the viewfinder. An easier solution is stopping down to increase depth of field, which will to some extend offset the field curvature problem.


Using a wide angle lens present other possible problems, though. One is that there is inevitable optical distortions with wide lenses, one of which causes subjects nearer the edges to be exaggerated and look larger than they are. You can see some of this occuring in the ceiling light panels (which also show "perspective" distortion). But I'd also bet that the ladies at either end of the row don't have that large an arm, as the one nearest the edge of the image appears in the photo. This is called "anamorphic" distortion and is an optical effect that's unavoidable with wide angle lenses. It's one reason most portraiture is done with standard to short telephotos, instead. The best solution is to back up farther and zoom to the 30mm or 50mm range... i.e. to avoid using wide angles for group shots like this. But to do so will require adequate working space and a stronger flash.


Which brings us to yet another consideration.... when shooting a Canon camera and flash in any of the auto-exposure modes, the camera will set exposure according to the ambient light, and then the flash will be fired as FILL.... about 1-2/3 stops underexposure automatically. If you want the flash to be the main or primary light source, you need to set the camera to M or Manual mode. So long as the flash is set to ETTL, the camera then will ignore ambient light for exposure calculations and will fire the flash as strongly as needed for illumination... In other words, you still get auto-exposure even though the camera is set to M. However, now it is being done with FULL flash.


Only problem is, if you are using the camera's builit in flash, it may not have enough power for this wide a shot at this distance. Built-in flashes are notoriously wimpy. If using an external 430EX or 580EX or similar flash, you would have ample light for the purpose, as well as better/more even wide angle coverage (using the flash's built in wide angle diffusion panel.)



Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories