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Beginner with Canon 40D 28-135 focusing issue (2 images)
Hello, I am having an issue with the camera focusing on the entire subject. I am taking some practice pictures around the house and finding that the camera pics the closest item to the lens and focuses solely on that. I have playing a bit with the manual focus and increased the aperture. But still no luck. I am taking very close picture of some Lego sets I have and they are coming out blurry. Here is some samples of the issue I am having..

The first one I have the gun in focus and the second one the men are in focus, I am trying to get both of them in focus and the background blurred..

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Comments (19)

You need more depth of field, which you will get by reducing the aperture (larger f-number)..

The smaller aperture will also reduce the background blur. Restore this by moving the background further away and/or using a longer focal length...

Comment #1

Winty,.

It sounds like you are pretty new to Photography/SLR in general..

I'd suggest you pick up the book "Understanding Exposure" by Bryan Peterson. It is a great book to help you understand the relationship between Apeture, Shutter Speed, and ISO..

Http://www.amazon.com/...g-Exposure-Photographs-Digital-Updated/dp/0817463003.

=Glen=-.

Http://www.pbase.com/gsansoucie..

Comment #2

I see you used a flash. Set your camera on manual, f 5.6, 1/60th of a second, flash exposure compensation +2.3, and let us know how it works for you..

Jerryhttp://jchoate.zenfolio.com/..

Comment #3

Do a bit of research on DOF (Depth of Field)..

For the job in hand.

You need a small aperture say f22 or f32 but then you find it's too dark, so you have to bump up the ISO to 800 or so if it's still too dark you need to supply some extra light. general rule of thumb to get the most part of a scene in focus you pick a focus point about 1/3 into the scene..

If you use flash you will get more in focus but have a "harsher" looking scene Strong Shadows can enhance or detract, so experiment with bouncing or difusing the flash.Above all, give it a go, it's the best way to learn..

FWIW you can use what you are doing do great advantage by focusing on one object with a wide aperture say f1.4 or f2.8 which will blurr out the background to enable the viewer to "see" the subject better, this blurring of the Backgorund called "Bokeh" is a highly prized feature of good quality lenses..

Take a good close look at a lot of professional shots of products in Magazines where they use this feature a lot...

Comment #4

If you want to ask a question related to this subject the you just did, if you want to ask a question of your own related to a new subject just click on new thread, put in a descriptive heading and fill it out in the body of the thread then click on Post...

Comment #5

Thanks for all the responses, yes I am new to the SLR's I will look into the book that was suggested. I did take a few pics with the aperture at 22 and it was a bit better. Burrs easily, I have been taking the pics using a tripod and the delay timer to help with camera shake. I did use manual focus to get it the way I wanted. I will try some of the suggested adjustments and let you know...

Comment #6

I do understand what aperture does and how it affects the picture. I was watching a youtube video about soft focusing on where the high f-stops gives the entire picture detail or sharpness and a low f stop gives just the focal point sharpness and blur everything else which is less distracting. And the ISO is the films response time to light. What distance should I be taking the picture at? Close as possible or back 3 or 4 ft and then zoom in? Should one of my first purchases be a light meter? I believe this is one of my problems. I assumed the camera would auto adjust for proper exposure...

Comment #7

Winty03 wrote:.

I do understand what aperture does and how it affects the picture..

OK, then you KNOW the answer to your "issue". Use a smaller aperture!.

Should one of my firstpurchases be a light meter? I believe this is one of my problems.I assumed the camera would auto adjust for proper exposure..

But the camera did adjust for proper exposure, exposure looks fine. How was the camera to know that you wanted the WHOLE scene in focus? That's why there is Av mode .

I think you don't know as much as you think. Peterson's "Understanding Exposure" is a good introduction to some of the basics of photography. Good luck and enjoy your new 40D!..

Comment #8

Egordon99 wrote:.

Peterson's"Understanding Exposure" is a good introduction to some of the basicsof photography. Good luck and enjoy your new 40D!.

Agreed - this is a good place to start. A light meter won't help because you still need to understand how metering works. Once you do, things will come much easier..

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Comment #9

Winty03 wrote:.

I do understand what aperture does and how it affects the picture. Iwas watching a youtube video about soft focusing on where the highf-stops gives the entire picture detail or sharpness and a low f stopgives just the focal point sharpness and blur everything else whichis less distracting..

Another point to be aware of is that there is *much* less depth of field when working with very small subjects. This is why you have had to stop down to f/22 as you mentioned in another post. The problem which then arises is lack of light, especially indoors..

And the ISO is the films response time tolight..

Yes, but high ISO speed means lower quality. Use ISO 200 and a slow shutter speed - luckily your subjects are not going to move so with a tripod it doesn't matter how slow the shutter is. I've taken shots like this with exposures of up to two or three seconds..

What distance should I be taking the picture at? Close aspossible or back 3 or 4 ft and then zoom in?.

It doesn't matter, at least not with regard to depth of field. However the perspective changes so you might find you like one better than the other - being close is more 'involving'..

Background blur is greater with a longer lens (i.e. move back then zoom in) but only for distant backgrounds. When the background is close the opposite can happen - so experiment..

Should one of my firstpurchases be a light meter? I believe this is one of my problems.I assumed the camera would auto adjust for proper exposure..

No, the camera's metering should work well. What problem are you having?.

Your first purchase should be lighting...

Comment #10

Thanks for the responses guys. I played around a bit over my lunch break. Question when you wish to have the entire picture in focus...say high f stop like 22 or so should I also be in the AV mode? Which I am reading gives aperture priority? I did take a picture at f22 and ISO 800, still parts blured. I know that the lighting is terribel in that room. Would maybe a different room or better lighting be the trick? If so how do you compensate when you can't change the pictures setting? All the tweaking you have to do seems like the macro (flower) setting seems worthless? Am I wrong?..

Comment #11

How close were you to the objects you photographed? You may have been too close..

Did you use a tripod? At 160mm, you should have had a shutter speed of about 1/200th of a second..

Did you, in fact, use a flash? If so, you might need to use a slightly slower shutter speed (check your manual)..

Using a depth of field calculator for a focal length of 160mm, an f stop of 16, and a distance from the objects of 3 feet, your depth of focus would have been 0.05 feet, which is only about a half inch. If you back up to a distance of 10 feet from the objects, the depth of focus would increase to 0.69 feet, or about 8 inches. Therefore, try backing up!.

Jerryhttp://jchoate.zenfolio.com/..

Comment #12

Ya I was pretty close I would say within a foot at most 2 ft away. When I get some time tonight I will try those settings. Ya I was using a tripod and was varying the zoom on it. Trying to get something clearer. Question would chaing the auto focus from the all setting to just the center, work? Using the macro preset? Was thinking of trying that too. Thanks..

Comment #13

Remember that at any given aperture value the depth of field will be MUCH greater at the wide end of that lens than it is at the telephoto end. At the 28 end that lens probably doesnn't have an aperture large enough to shallow the DOF (would require somethign in the 1.2-1.8 range) where as at the 135 end even 4.0 is pretty shallow...

Comment #14

SMPhoto wrote:.

Remember that at any given aperture value the depth of field will beMUCH greater at the wide end of that lens than it is at the telephotoend..

Not if the subject magnification (framing) is maintained by increasing the subject distance then zooming in - which is what the OP asked about. In that situation the depth of field is constant...

Comment #15

The comment about backing up is not really very helpful because the whole image will be much smaller with the same focal length. If you increased the focal length to get the same image size then the depth of field will be right back to where you started..

The whole depth of field issue causes lots of confusion and in this instance the thing that seems to be missed is that when taking pictures very close up (macro) then the depth of field will always be small. Reducing the aperture to F22 of even smaller will give the most depth possible but it will still be quite limited when working at very close distances..

Back the the original post the "Canon 40D 28-135 focusing issue" the title my mislead. There is not an issue with this camera and lens issue. There is not really an issue with the photographer either. The only "issue" is about how much the photographer has yet to learn and the photographer has quite rightly asked the question in a beginners forum..

The photographer has also been experimenting with the camera which is always a really good way to learn..

My only other advise to the poster would be to find a good evening class for beginners, I know of a number in my part of the UK (I teach one of them) but I'm sure they may be found elsewhere as well..

Good Luck.

SeamusShaysart - Capturing your Dreams..

Comment #16

Thanks for all the responses and ideas, I know it's just me an inexperienced photographer. I just was asking for some assistance and get some knowledge I will look into some photography classes. Thanks again...

Comment #17

Steve Balcombe wrote:.

Not if the subject magnification (framing) is maintained byincreasing the subject distance then zooming in - which is what theOP asked about. In that situation the depth of field is constant..

That is only true when the subject distance is much less (about 1/4 less) than the hyperfocal distance. Since there are suggestions to shoot at f22 with his lens (28-135), the hyperfocal distance at 28mm at f22 is at 6.07 ft for the 40D. Note, this rule also breaks down with macro photography..

From the following site, it shows a graph of how a 28mm and 85mm lens deviates from this rule of thumb. Note that this chart is for a FF camera. The DoF for the 40D would be less for both lenses (since it has a smaller CoC), but the curves would be similar..

Http://www.dofmaster.com/dof_imagesize.html.

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Comment #18

Dave_s93 wrote:.

Steve Balcombe wrote:.

Not if the subject magnification (framing) is maintained byincreasing the subject distance then zooming in - which is what theOP asked about. In that situation the depth of field is constant..

That is only true when the subject distance is much less (about 1/4less) than the hyperfocal distance..

I didn't mean to suggest it was mathematically identical (you have to be so careful with every word on this forum!), I meant that for all practical purposes it was the same..

Since there are suggestions toshoot at f22 with his lens (28-135), the hyperfocal distance at 28mmat f22 is at 6.07 ft for the 40D..

That is the most extreme example for this lens, and even in that case the OP is shooting at around 1/4 of the hyperfocal distance. But in any case the rule remains true to a fairly good approximation well beyond that..

Remember that what I was trying to do was give a one-sentence refutation of the previous post which was somewhat missing the point. I'm familiar with much of the additional detail but it doesn't belong here, it would just add to the confusion..

Note, this rule also breaks downwith macro photography..

Actually it is pretty close at 1:1 - but we are nowhere near that here..

From the following site, it shows a graph of how a 28mm and 85mm lensdeviates from this rule of thumb. Note that this chart is for a FFcamera. The DoF for the 40D would be less for both lenses (since ithas a smaller CoC), but the curves would be similar..

Yep, I'm familiar with that. Note that although the in-focus range shifts towards the camera at greater focal lengths, the *total* depth of field remains the same to a fairly good approximation - until the rear depth of field goes shooting off to infinity, at which point we are no longer too worried about precise measurements!.

Another point worth making is that at these distances there can be a significant difference between an idealised thin lens formula and the actual performance of a complex zoom lens. All these 'rules' and graphical representations are of limited accuracy in practice. But we can learn a lot from the basic trends, and the numbers are useful as long as they are understood to be approximate..

But how much of this does the OP need to know? Stop down to f/16 or f/22 to get enough depth of field, and use whatever focal length you prefer because it won't make a big difference to depth of field. A wide angle lens and correspondingly shorter subject distance will give a more involving perspective but less background blur. That's about it - in two sentences..

Http://www.dofmaster.com/dof_imagesize.html..

Comment #19

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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