Digital Rebel+ef28mm 2.8=blurry... help

[enigma]

Hi all!

I am new here.

I have the digital rebel and I am quite happy with it. Since the standard zoom is not exactly great, I wanted to go for some prime lenses. I started with the ef28mm 2.8 to get something similar to a 50mm (28x1.6 is about 45).

Now, my pictures with the 28mm is most often a huge dissappointment. The camera cannot seem to focus properly with this lense. At least not for nature shots where you want maximum depth of field (the lense is hard to focus by hand).

Did any of you had the same experience?

Do you know a trick for how to set the focus manually for greatest depth of field for e.g. aperture 8? On a normal camera with a 50mm lense, you should focus at about 11m, which will give you focus from 5.5m to infinity. But 11m is of course not marked on a 28mm lense. The markings stop after about 5m. And where, exactly, should it be set for this combo? I am lost here... and my pictures all blury all over :(

By the way, when I look in the fileviewer at the autofocus red spots, they indicate that focus is exactly where I wanted it. Still, the pictures are a blur.

I do not think that it is something wrong with the lense, since it gives tack sharp pictures for motives closer to the camera.


Thanks for reading!

[DieselGirl]

Post a sample shot for us if you can.

[enigma]

OK, do not get a headache:-)

According to the software, focus is right on the treeline!!!

http://user.it.uu.se/~johans/cedar.jpg

Tnanks![/img]

[c0ntr0lz]

what are the settings for that photo?
it doesn't look to bad
but it is a WA so you may have some trouble with crispness for landscapes.

[Spargo]

Looks fine to me...

[drisley]

A little sharpening would fix that nicely.
However, I noticed you used F8.
Perhaps a smaller aperture, around F11 would improve it.

[blinking8s]

yeah, id say go with the smaller apature...the AF on the 300d can be shady, i have a tendency to triple check my focusing on the camera

[enigma]

Thanks for all replys so far. The settings for the picture follow. Questions for some replyers come first.

Question for Drisley: Would you say stopping down to f11 is necessary on that lense? I was under the impression that f8 was its "best" aperture.

Moreover, Drisley, my pictures taken with the standard zoom look great after sharpening. This one looks horrible when I try. The focus is not really there.

Question for c0ntr0lz: What is WA? Why does it give trouble with crispiness for landscapes?

Spargo: When you say that it looks fine, what are your references? Maybe I should post a second sample, where the AF got it right?

Moreover, what sharpening settings in Photoshop do you guys use for a 6Mpixel RAW unsharpened image? I use unsharp mask 200% and radius about 2.0. Comments? (Note that my sample is NOT post processed).

Last, any ideas on how to set the focus manually for maximum depth of field?


Thanks again to all!

Settings for the sample pic:
File Name
CRW_1649.CRW
Camera Model Name
Canon EOS DIGITAL REBEL
Shooting Date/Time
9/9/2004 11:26:49 AM
Shooting Mode
Manual
Tv( Shutter Speed )
1/320
Av( Aperture Value )
8.0
Metering Mode
Center-weighted averaging
ISO Speed
100
Lens
28.0 mm
Focal Length
28.0 mm
Image Size
3072x2048
Image Quality
RAW
Flash
Off
White Balance
Daylight
AF Mode
AI Focus AF
Parameters
Contrast +1
Sharpness +1
Color saturation +1
Color tone Normal
Color Space
sRGB
File Size
8022KB
Drive Mode
Single-frame shooting
Owner's Name
Camera Body No.
0960343687

[drisley]

I'm not a landscape photographer by any means, but even if the sharpest aperture for a lens is F8, when you are shooting such a large area it's good to keep the aperture as small as possible (I think F11-F16 is used by most landscape photogs).
Depending what zoom lens you are comparing it to, the 28F2.8 may just not be as sharp. Even the Tamron 28-75F2.8 is said to be much sharper than the Canon 17-40L at the same focal length and aperture.
I'm not familiar with the quality of the 28F2.8.

WA=Wide Angle

[malla1962]

Hi all!

I am new here.

I have the digital rebel and I am quite happy with it. Since the standard zoom is not exactly great, I wanted to go for some prime lenses. I started with the ef28mm 2.8 to get something similar to a 50mm (28x1.6 is about 45).

Now, my pictures with the 28mm is most often a huge dissappointment. The camera cannot seem to focus properly with this lense. At least not for nature shots where you want maximum depth of field (the lense is hard to focus by hand).

Did any of you had the same experience?

Do you know a trick for how to set the focus manually for greatest depth of field for e.g. aperture 8? On a normal camera with a 50mm lense, you should focus at about 11m, which will give you focus from 5.5m to infinity. But 11m is of course not marked on a 28mm lense. The markings stop after about 5m. And where, exactly, should it be set for this combo? I am lost here... and my pictures all blury all over :(

By the way, when I look in the fileviewer at the autofocus red spots, they indicate that focus is exactly where I wanted it. Still, the pictures are a blur.

I do not think that it is something wrong with the lense, since it gives tack sharp pictures for motives closer to the camera.


Thanks for reading! what a nice pic,iwould be happy if most of mine were like that :lol:

[drisley]

BTW, just as a comparison, have a look at this landscape shot taken with the 20D at F9 and 24mm.
http://web.canon.jp/Imaging/eos20d/downloads/landscape1.jpg

Personally, I dont think it's any sharper than your landscape shot.
And the lens used was the Canon 24-70L which is worth $2000CDN!

Wide angle landscapes usually just arent as sharp as say, portraits or pictures of people. I shot my first "landscape" with the ridiculously sharp 135F2L, and it was no where near as jawdroppingly crisp as the portraits/ candids I take.

[robertwgross]

Did you have any filters on the front of the lens, like UV?

---Bob Gross---

[enigma]

Yes, I used an UV filter, as I was in the Sierra Nevada. Could it affect negatively?

Thanks!

[slin100]

Now, my pictures with the 28mm is most often a huge dissappointment. The camera cannot seem to focus properly with this lense. At least not for nature shots where you want maximum depth of field (the lense is hard to focus by hand).

Did any of you had the same experience?

I had very similar results with the EF 24/2.8 and a 10D. At first, I attributed the overall mushiness to the "Canon DSLR softness". I eventually discovered the 10D would backfocus with that lens, so I returned it and got a 17-40/4L. What a revelation! That's probably not what you wanted to hear.

Anyway, I really doubt closing down to f/11 would have changed the result much. At f/8, the lens ought to have been focused close enough to the hyperfocal distance to not have affected the result much. You could have tried switching to A-DEP mode, focused the lens, switched to manual focus to lock focus, switched to Av and taken the shot.

[robertwgross]

Yes, I used an UV filter, as I was in the Sierra Nevada. Could it affect negatively?

Thanks!

Every once in a while we hear of a person with strange lens softness, and then they remove the UV filter. VOILA! The image sharpens up.

I don't know exactly how or why, but it is awfully easy to test.

We guess it might have to do with either an extremely dirty filter, or an extremely cheaply manufactured filter, or maybe one that got mounted crookedly in its mounting ring.

Why does UV relate to the Sierra Nevada?

Granted, the Sierra Nevada has elevations slightly higher than average, and there is more UV light there. So what? Your camera's sensor has a UV filter over it anyway. About the most practical use for a UV filter is to help prevent damage to the main lens front element.

---Bob Gross---

[drisley]

You could have tried switching to A-DEP mode, focused the lens, switched to manual focus to lock focus, switched to Av and taken the shot.

That's an excellent tip! :)

[robertwgross]

Could there be a camera shake problem? That results in images that are mostly sharp, but not completely sharp.

---Bob Gross---

[BDM]

I tend to rule out camera shake because of the relatively high shutter speed and wide angle lens. Bob's earlier question about filter use raised a more likely issue in my opinion. Poorly made filters, especially with wide angle lenses can easily degrade an image.

I would avoid the use of unnecessary filters whenever possible. A UV filter in this situation is not needed in my opinion. It is another set of glass surfaces which can collect dust and dirt, contriobute to flare and, if not absolutely optically flat and of the proper thickness, can really hurt the definition.

I took several workshops many years ago from John Shaw. He was opposed to the use of unneeded filters and gave a lot of cogent reasons. Take a look at his work if you are not familiar with it. He has a web site. His shots are just razor sharp and are something else to see projected on a screen. Yes, he is a Nikon user but his techniques are universally applicable in my view.

Bruce

[enigma]

Thanks for many good replies!!!

The picture was taken with a tripod, so I rule out camera shake.

Hmmm. The UV filter was about 35$ and almost brand new. But I did not know the Dig Reb had a "built-in" UV filter. I will do some testing without the filter.

The focusing idea is interesting. But here is what I want to do:

1. Assume that f8 is the "best" aperture.

2. Theoretically, for getting the maximum depth of field for a 50mm lense at f8, one should focus at 11m (=about 35 feet). This would give focus from about 5.5m (about 17 feet) to infinity.

3. By trial and error (phew!) find this exact focusing point on my 28mm lense (28x1.6=45) (of course there is no marking for 35 feet on a WA) AND MARK IT (with a pen/tape or whatever). This mark will be VERY close to the infinity mark.

4. Then for nature shots, just switch to manual focus and set it to the mark (given that nothing in the picture closer that 17 feet needs to be in sharp focus).

Any other ideas?

Thanks!

[EXA1a]

4. Then for nature shots, just switch to manual focus and set it to the mark (given that nothing in the picture closer that 17 feet needs to be in sharp focus).

Any other ideas?

Thanks!
I definitively wouldn't try to manually a WA AF lens according to a mark on the barrel. Can't imagine you'd be close to what the AF can do. Manual focusing is difficult with a 300D anyway because you don't have the proper focusing screen to do it and the (at least my) dRebel's focusing screen isn't sharp in the center.
I'd propose to switch to center point focusing, focus on something which is 17 feet away (to be on the safe side, don't go below 20 feet) and if you're shure the lens has focused correctly, switch off AF, frame, and shoot.
BTW: The picture looks very good to me, I don't understand your complaint!
--Jens--

[robertwgross]

Was the photo taken at Zumwalt Meadows in Fresno County, California?

---Bob Gross---

[enigma]

Your eyes are good, Bob!

California, Fresno County, Kings Canyon National Park, Cedar Grove, Zumwalt Meadows. Right on!

If I only had more time there. I love the place!

[roanjohn]

There is nothing wrong with this pic............this pic is sharp sharp sharp!!!

Post-process...........that is key. If this was my starting image, I would be a very happy man.

Ro1

[Bruce Foreman]

Hi all!


Now, my pictures with the 28mm is most often a huge dissappointment. The camera cannot seem to focus properly with this lense. At least not for nature shots where you want maximum depth of field (the lense is hard to focus by hand).

Did any of you had the same experience?



In the '70's when I could finally afford my first Nikon's, I had some problems with 28mm Nikkor lens sharpness. I was in Taipei and a Chinese photographer I knew took me to the Nikon repair shop there and "Lao Wang" (Old Wang) put the lens on a machine that measured lens element centration. He found it to be off by 11%. He told me that the 28mm lens formulas were the most difficult to get "right" and that one in 3 were "soft", the rest were variations of "OK" to pretty good.

I took that lens back to the Navy exchange where I bought it and exchanged it for another one. Took it to the repair shop, Lao Wang read it and found it to be 7% off. He said that would be OK but that if I wanted sharp pictures I would be forever chasing something just barely out of reach.

The third lens read 3%. Lao Wang said that was as good as it gets in that lens formula. Pictures were pretty sharp with decent contrast.

You may be seeing something similar. Send it to the official warranty station and request lens parameters be read, recorded, and provided to you. Expecially lens element centration.

I, too, have the Digital Rebel and am fairly content with the kit lens.

Bruce Foreman
Some cameras, some lights, and some stuff...

[Bruce Foreman]

On second thought...

Don't put yourself to any inconvenience by sending that lens anywhere. I just took a second, longer, lingering look at your picture and find nothing lacking in the sharpness.

I would follow the others suggestions about taking the UV filter off and just be sure you always have a clean microfiber lens cleaning cloth with you.

The picture is quite sharp, I looked closely at near detail close to the river and find nothing that needs to be any sharper.

28mm is a wide angle for full frame 35mm format, the lens formula is more complex than other focal lengths and resulting softer contrast from more lens elements may contribute to an illusion of less sharpness.

Use it and enjoy it! It looks like a good lens.

Oh...Really nice scenic photo, by the way.

Bruce Foreman
(wish I was there...)

[robertwgross]

Your eyes are good, Bob!

California, Fresno County, Kings Canyon National Park, Cedar Grove, Zumwalt Meadows. Right on!

If I only had more time there. I love the place!

To my best guess, if you had moved about five feet to the right, and then looked down at the ground, you would have seen a rock with my initials carved on it.

The topography gets a little more interesting several miles east of there around Avalanche Pass. Then better yet east of there up Bubbs Creek.

---Bob Gross---

[enigma]

Thanks again to all repliers! This is getting very interesting!

Despite that many here on the forum judge the picture as "sharp enough", I still think it's way too blury. Gives me a headache:-(

But many have mentioned postprocessing, which of course is the next step. I have really tried doing this in Photo Shop, but I do not seem to get itr right.

First I convert to AdobeRGB and save as tiff. Open in PhotoShop.

I use unsharp mask with 200% and a radius of 2.0. Does this make sense? How would YOU attack this picture? Tell me if anybody wants to play with the RAW file, and I'll ship it right away.

Thanks all!!!