Autofocus - Is it normal?

[ted_dbear]

I am relatively new to digital SLR use and all my film cameras were manual focus. So I am not sure if this is normal or not

hence the question:

 

I am using a E510 with either the 14-45 or 35mm lenses. It seems like when the subject is over 5 meters distance nothing is

focus. It is not comepletely out of focus but is not also sharp as I expect those lenses to be. I have tried to focus on

specific items such as tree trunks, specific objects, ... then enlarge the photo and see if they were in focus and they are

not. On the other hand in micros they are sharp and rasor (specially with the 35 mm lens which is very good).

Is this normal for autococus camersas?

1. If you are taking photos at landscape or large outdoor objects (buildings.etc...) how do you focus?

2. would you use S pr C focus?

3. can anyone post some outdoor/landscape images (full size) taken with 510 or similar cameras so I can see how they are

supposed to be?

4. finally how do you test to see if your autofocus is defective?

 

Thanks a million in advance.

[ted_dbear]

To illustrate I have posted a sample at : http://www.software-farm.com/sample.jpg (about 2 M)

[ishi_p]

So are you are saying the 35mm macro does auto focus ok?

 

If so the auto focus is fine. I would say it has more to do with the quality of the zoom. I think you will struggle to get

much better per pixel sharpness from an entry level zoom if that’s what it is. I have rarely been impressed with the

quality of wide angle zoom's, especially on less than 35mm size sensors Thay have so much more detail to

capture in a wide view and I hear sensors have problems with capturing light at oblique angels.

 

Perhaps there are others with more experience with this lens that could give you a better idea what to expect. I take

it's the F3.5 – whatever. Not the 2.8. I would hope for more than that anyway.

 

I think I will stick with my primes.<div></div>

[starvy]

ted, how sharp are the pictures when you manually focus? is there any noticeable difference?

[ted_dbear]

Starvy Manual focus does a better job whenever I can do any manual focus properly. With the tiny viewfinder and lack of

any focus indicators (like the old manula cameras) it is had to do a good job of manual focus on digital.

Ishmael 35 does a good job only in macro not all the time. In fact the sample is taken with a 35mm but since it is a

landscape I have hard time finding any focused point in it.

It is not due to shaking of camera (I use IS plus a tripod often).

The the Bear

[ishi_p]

Judging by the full size samples on DCRP-Review, you’re not going to get this much better. It looks as sharp as them, (so in this sample) I would not say it’s out of focus.

 

I can only suggest you shoot raw and process yourself, or buy a better lens.

 

I use live view on my L1 if I want to be sure. I would never expect a budget camera to be near 100% at auto focus. But as I say it’s not the issue in this sample.

 

PS. I Sorry for my mistake. I missed the 2 are's in my first post.

[jim nichols]

I would offer two points, from my experience with my E-510 and the Zuiko 14-54 lens. First, I researched the kit

lenses, and decided that I would not be happy with the 14-45. This led me to buy the 14-54 instead, because it

gives better results. Second, I set my 510 to use the center focus point only. Otherwise, the camera can

sometimes focus in the wrong place when there are options in the field of view. I have not been disappointed

with the results.

 

Try this link, and click on the symbol at the top or bottom to get the larger view.

 

http://gallery.leica-users.org/v/OldNick/The+Neighborhood.tif.html

[jim nichols]

Better link.

[jim nichols]

I forgot that TIFF would not work here. Another link.<div></div>

[Tom Wiggins Photography]

I think Jim has hit on the point. Auto focus looks for a contrast point in the image, I do has he suggested and set the focus on my E510 to the center, that way I am sure to get the subject in focus.

[steven_f1]

Ted, I think the problem in the photo you attached is that the sky is over exposed. Over exposing the sky can reduce the sharpness of the tops of the trees. Try repeating the image but adjust your exposure so that the sky is properly exposed. The rest of the image looks OK.

[ted_dbear]

Thanks for the replies.

I use the center points to have a btter sense of where I am supposed to be focused too.

Are there any technics in shooting landscape or outdoor shots to make it a better shot?

I was told that higher f points (8,16, ....) result in better depth of field, I try to use that. Do you know of other tricks and techniques to imporve the picture.

Quite frankly if you all think this is as good as AF going to give it is quite disapointing comapare to any old film camera.

Ted the Bear

[r.t. dowling]

If you're using a tripod, be sure to turn off the I.S. It can sometimes try to compensate for camera shake even when there is none, thus resulting in an unsharp image.

[wharridge]

Ted,

 

I downloaded your sample and had a look at the EXIF data, it tells me you had sharpness=soft and contrast=soft. You might find that the images "look" sharper if you set the sharpness and contrast a bit higher in camera or apply some USM in post processing.

 

...Wayne

[matthew_newton]

On a 4/3rds camera anything over about f/8 or f/11 is going to reduce the image sharpness due to difraction. The 4/3rd sensor is pretty tiny. The limit of difraction is about f/16 on 35mm film/sensor, about f/11 on APS-c sized sensors (or film if you have an APS film camera) and around f/8 on 4/3rds. So using f/16 is going to reduce the sharpness at least slightly compared to using f/8. Try doing two identical exposures (leave the focus locked) at f/8 and f/16, I think you'll find that the f/16 shot is very slightly softer then the f/8 shot.

[ishi_p]

The above suggestions seem good. I have heard that about I.S.

 

The optimum aperture for a 4/3rds camera is normally wider than f8 but this depends on the lens. I would say around

5.6 for many

 

Also (I hope I don’t get flamed for saying this) but Canon say in there white paper that the full frame 1ds (Mk2 I think)

has only just reached the resolution of 35mm colour film. So when you consider you have half that and you are

shooting wide angle on an area ¼ the size 35mm film, your lens is having to be 4 times as good on about half

resolution.

 

 

Also when you shoot digital the sensor intentionally blurs the shot requiring you to use USM in many cases.

 

There are also copy inconsistencies with any lens so you may have a not so good copy.

 

Don’t get me wrong I hate USM But I am getting better at using it so i don’t have many artefacts. The image

looks quite processed anyway so it’s more difficult to work with than raw, but I had a go. I hope this crop below

shows up.

 

Also if you zoom in on your image you will see that the pixels are recording about as much as they can (the edge of

the lamp post being about 1 pixel wide). You are not going to get much better than this on a Bayer type sensor of

that resolution. Maybe a little, but not much. The only sensor type to look tack sharp at 100% size is Foveon. I

don’t use it because I find it harder to work on an image that’s so small. 3-4 mp

 

Personally I feel if you just look at your picture at screen size it’s nice. So maybe with a little USM a 10x12 print

would be satisfactory.<div></div>

[ted_dbear]

More thanks for the replies. I have other questions I think I better start a new thread for that one. But thanks for the help everybody.

[paul_p3]

You have been warned! :-) Also, as an earlier posted mentioned, don't use IS when the body is on a tripod, your comment gave the appearence that you do this (sometimes?)

 

I think one poster hit the nail when he reported that you have the camera set up with low "Sharpening" and "Contrast" settings. Bump them up, especially the former, and you should be happier... or bump them up when you convert the raw file.

 

I too have had a beef with Olympus/four-thirds 'lack of resolution' or 'bluriness':

 

http://www.photo.net/olympus-camera-forum/00R8mw

 

... but when I stood back and considered things afresh, I think I was simply expecting too much. And having the ability to look into images at 1:1 [100%] did more harm than good as it caused doubts. Look at your images 'zoomed out' and any 'unsharpness' goes.

 

Re: a duff 14-45. Well it isn't impossible but from what I gether, the standard 'kit' lenses are very well thought of and it is just their build quality, when compared to their higher tier stablemates, that is lacking.

 

http://www.wrotniak.net/photo/43/std-zoom.html

 

and

 

http://web.archive.org/web/20070813231330/www.photozone.de/8Reviews/lenses/olympus_1445_3556/index.htm

 

Quote

 

"Verdict

Regarding its price tag the Olympus 14-45mm f/3.5-5.6 is a very good deal with a good build quality combined with a very decent optical performance. The most pronounced weaknesses are very strong barrel distortions at 14mm and some chromatic aberrations at 14mm @ f/3.5 (easily correctable via tools)."

 

Happy photography!