Canon 17-55mm 2.8

canon400d

I think as you know I have just received my 17-55mm 2.8 and I am really thrilled with it. However, I have taken a few shots on 2.8 and expected the background to be blurred but not so. I have posted some photos of Highland Cattle on Cool Shots Forum and you will see what I am talking about.
Was I too near the subject for the blurring to take place or what? I took some shots today pf a monument on 2.8 and once again the DOF was if I had taken it on F22. Any suggestions would be more than appreciated.
Regards
Bob

Nikolai

canon400d wrote:

I think as you know I have just received my 17-55mm 2.8 and I am really thrilled with it. However, I have taken a few shots on 2.8 and expected the background to be blurred but not so. I have posted some photos of Highland Cattle on Cool Shots Forum and you will see what I am talking about.
Was I too near the subject for the blurring to take place or what? I took some shots today pf a monument on 2.8 and once again the DOF was if I had taken it on F22. Any suggestions would be more than appreciated.
Regards
Bob

And the images are...?

DavidTO

Nikolai wrote:

And the images are...?

And EXIF would help, too.

canon400d

DavidTO wrote:

And EXIF would help, too.

Hi
This was the photo I produced on Cool Shots Forum it was taken at 2.8 at 100 ISO and the focal length was 45mm. I hope this will help you to solve my problem David as you have helped me out many times before.
Regards
Bob

Nikolai

canon400d wrote:

Hi
This was the photo I produced on Cool Shots Forum it was taken at 2.8 at 100 ISO and the focal length was 45mm. I hope this will help you to solve my problem David as you have helped me out many times before.
Regards
Bob

Assuming you're shooting from about 10 ft, DOF master shows about 1.6ft of DOF. Kinda matches the image.
Did you expect stronger blur? You need to use longer focal length then and shoot froma a greater distance.

canon400d

Nikolai wrote:

Assuming you're shooting from about 10 ft, DOF master shows about 1.6ft of DOF. Kinda matches the image.
Did you expect stronger blur? You need to use longer focal length then and shoot froma a greater distance.

Thanks Nikolai
Yes you are probably quite right as I was only about 7 feet from the beast. I am sure if I had been further away there would have been more blur. Having said that what about portraits or wedding shots blurring backgrounds? I understand this lens is perfect for both portraits and wedding shots. I must add I am not taking photos for money it is a total hobby but would like to be on top of the job if you know what I mean.
Regards
Bob

pathfinder

Bob, there are two factors that significantly affect DOF - aperture and distance from subject to film plane. Sensor size plays a modest role, shallower dof with full format, and even less for medium formats.

Here is a table you can look at to get an idea of what DOF to expect. DOF will get shallower with smaller distance from subject to image plane, and with larger apertures.

Focal length has no role in DOF IF the subject is kept the same size on the image plane.

So for shallower DOF, get closer and use a wide aperture.

Qarik

canon400d wrote:

Thanks Nikolai
Yes you are probably quite right as I was only about 7 feet from the beast. I am sure if I had been further away there would have been more blur. Having said that what about portraits or wedding shots blurring backgrounds? I understand this lens is perfect for both portraits and wedding shots. I must add I am not taking photos for money it is a total hobby but would like to be on top of the job if you know what I mean.
Regards
Bob

To get the nice creamy background bokeh (the blur):
1) shoot at highest zoom
2) shoot wide open
3) shoot as close to the subject as you can

You will have have to balance this with gettin gthisng in focus of course since DOF will be shallow at these conditions.

Scott_Quier

Qarik wrote:

To get the nice creamy background bokeh (the blur):
1) shoot at highest zoom
2) shoot wide open
3) shoot as close to the subject as you can

You will have have to balance this with gettin gthisng in focus of course since DOF will be shallow at these conditions.

Put another way, there is a small list of things that can be done to throw the background OOF. All else held constant...

1. The longer the focal length, the shallower will be the DOF. So, "highest zoom" will decrease DOF and increase the extent to which the background is OOF.
2. The shorter the focal distance, the shallower will be the DOF. So, the closer you are to your subject, the more will the background be OOF.
3. Aperture - the larger the aperture, the shorter will be your DOF and your background will be more OOF.
4. Subject to background distance. The further is the subject from the background the more will the background be OOF (assuming you subject is in focus).

Moving away from any of these extremes will decrease the extent to which your background will be OOF.

canon400d

pathfinder wrote:

Bob, there are two factors that significantly affect DOF - aperture and distance from subject to film plane. Sensor size plays a modest role, shallower dof with full format, and even less for medium formats.

Here is a table you can look at to get an idea of what DOF to expect. DOF will get shallower with smaller distance from subject to image plane, and with larger apertures.

Focal length has no role in DOF IF the subject is kept the same size on the image plane.

So for shallower DOF, get closer and use a wide aperture.

Hi Pathfinder that is a great chart and I have printed out to study, thanks a lot. I thought I was pretty ok with DOF and wide aperture for shallow DOF to give a nice blur. Anyhow, in this shot I was 7 feet away and I had it on 2.8 so do you not think the background should have been more blurred?
Regards
Bob

canon400d

Qarik wrote:

To get the nice creamy background bokeh (the blur):
1) shoot at highest zoom
2) shoot wide open
3) shoot as close to the subject as you can

You will have have to balance this with gettin gthisng in focus of course since DOF will be shallow at these conditions.

Thanks Quarik, I will certainly try out what you have said but I must admit I did that in the shot which I have outlined.
Regards
Bob

canon400d

Scott_Quier wrote:

Put another way, there is a small list of things that can be done to throw the background OOF. All else held constant...

1. The longer the focal length, the shallower will be the DOF. So, "highest zoom" will decrease DOF and increase the extent to which the background is OOF.
2. The shorter the focal distance, the shallower will be the DOF. So, the closer you are to your subject, the more will the background be OOF.
3. Aperture - the larger the aperture, the shorter will be your DOF and your background will be more OOF.
4. Subject to background distance. The further is the subject from the background the more will the background be OOF (assuming you subject is in focus).

Moving away from any of these extremes will decrease the extent to which your background will be OOF.

Thanks ever so much Scott, as I explained I was only about 7 feet away and I had my aperture on its widest at 2.8 for the 17-55. Do you not think the background should have been a bit more blurred. ?
Regards
Bob

Nikolai

canon400d wrote:

Thanks ever so much Scott, as I explained I was only about 7 feet away and I had my aperture on its widest at 2.8 for the 17-55. Do you not think the background should have been a bit more blurred. ?
Regards
Bob

Because the focal length is kinda short..

pathfinder

canon400d wrote:

Hi Pathfinder that is a great chart and I have printed out to study, thanks a lot. I thought I was pretty ok with DOF and wide aperture for shallow DOF to give a nice blur. Anyhow, in this shot I was 7 feet away and I had it on 2.8 so do you not think the background should have been more blurred?
Regards
Bob

Your background is blurred, Bob, it is not sharp.

But it is not the kind of bokeh one sees with a 200mm f2.8 or a 400mm f2.8 at that close a distance. 7 feet is not really that close to the film plane for a 45mm lens.

Try using you depth of preview button on your camera - press the preview button at the base of your lens mount, watch the aperture stop down and the image get darker - continue looking for about 10-15 seconds, until your eye adapts to the darker image, and then evaluate the depth of field looking through your lens to try to educate your eye as to what to expect when you press the shutter. Unless you are very close - say within two or three feet - you are not going to get that very blurry background with a 45mm lens.

I find using the depth of preview button easier, and more helpful, than stopping to look away from my viewfinder to look at a dof table. But I am old fashioned and old school. I suspect you are too, Bob!!

Scott_Quier

canon400d wrote:

Thanks ever so much Scott, as I explained I was only about 7 feet away and I had my aperture on its widest at 2.8 for the 17-55. Do you not think the background should have been a bit more blurred. ?
Regards
Bob

-- what he (PF and Nik) said!

canon400d

Scott_Quier wrote:

-- what he (PF and Nik) said!

Thanks Scott and Nik for replying. I think your explanation you have given Pathfinder is absolutely first class. I can follow every thing you have described. I have previously used the depth of preview button but it has never been explained to me the way you have. I will certainly use it again.
Thanks once again which I really appreciate.
Regards
Bob

studio1972

It's worth noting that the DoF is also dependent on the output medium. A small image on your computer screen will have more DoF as the blurring is negated by shrinking many pixels into one.

DoF charts make assumptions about what the image will be viewed on, so if you are looking at the image in a different format, the DoF will change.

studio1972

pathfinder wrote:

Your background is blurred, Bob, it is not sharp.

But it is not the kind of bokeh one sees with a 200mm f2.8 or a 400mm f2.8 at that close a distance. 7 feet is not really that close to the film plane for a 45mm lens.

Try using you depth of preview button on your camera - press the preview button at the base of your lens mount, watch the aperture stop down and the image get darker - continue looking for about 10-15 seconds, until your eye adapts to the darker image, and then evaluate the depth of field looking through your lens to try to educate your eye as to what to expect when you press the shutter. Unless you are very close - say within two or three feet - you are not going to get that very blurry background with a 45mm lens.

I find using the depth of preview button easier, and more helpful, than stopping to look away from my viewfinder to look at a dof table. But I am old fashioned and old school. I suspect you are too, Bob!!

I think that if you have the aperture wide open the button makes no difference, you are already seeing the DoF as in the picture. The only problem is that the image you are seeing is very small, and areas which look in focus may well be out of focus when printed at 10 by 8 etc.

pathfinder

That is correct - if you are shooting at f2.8 with a lens with a maximum aperture at f2.8, you will not see any change by pressing the DOF preview button, as the aperture does not stop down at all at f2.8 in a lens with a maximum aperture of 2.8. Kind of a tautology, right!

When using the DOF preview button, the image is not small, as you are looking through the viewfinder, and the image should be very close to life sized if viewed through a normal lens focal length. Won't work in the dark though.........but then you can't see anything through the lens in the dark either.

studio1972

pathfinder wrote:

When using the DOF preview button, the image is not small, as you are looking through the viewfinder, and the image should be very close to life sized if viewed through a normal lens focal length. Won't work in the dark though.........but then you can't see anything through the lens in the dark either.

I guess it might all depend on your eyes, but to me, when I look through the viewfinder, I see a similar level of detail to what I might see on a 7x5 print about a foot away. If fact, if I look through the viewfinder with one eye and have the other open the size of the rectangle roughly equates to to about 7" across about a foot away. Try it, see what result you get. I guess it would vary with camera model, mine is a 40d and 450d and the viewfinder seems slightly larger on the 40d (just checked the specs and that seems right). Looking at the specs it seems that a full frame camera might have a slightly larger viewfinder image. In fact, it seems that for canon the 1ds mkIII > 5d mkII > 40d.

Just goes to show that there are advantage with the top pro cameras that we don't even tend to talk about

If I look at a large print I see more detail than I get through the viewfinder, so something that looks in focus through the viewfinder might be slightly soft on a large print (say 12" plus).

pathfinder

The full frame cameras do have much brighter viewfinders, and larger viewfinder images. For bright viewfinders, look at an OM-2 or an FM3 from the 80's

canon400d

studio1972 wrote:

I guess it might all depend on your eyes, but to me, when I look through the viewfinder, I see a similar level of detail to what I might see on a 7x5 print about a foot away. If fact, if I look through the viewfinder with one eye and have the other open the size of the rectangle roughly equates to to about 7" across about a foot away. Try it, see what result you get. I guess it would vary with camera model, mine is a 40d and 450d and the viewfinder seems slightly larger on the 40d (just checked the specs and that seems right). Looking at the specs it seems that a full frame camera might have a slightly larger viewfinder image. In fact, it seems that for canon the 1ds mkIII > 5d mkII > 40d.

Just goes to show that there are advantage with the top pro cameras that we don't even tend to talk about

If I look at a large print I see more detail than I get through the viewfinder, so something that looks in focus through the viewfinder might be slightly soft on a large print (say 12" plus).

Thanks Sarah that is very interesting. I am still learning in my old age and hopefully I will get there.
Regards
Bob