D70 focus problems??

When I compare the pictures from my D70 and my PowerShopt G3 the G3
pictures seems very much sharper. This is the case even when I increase
the sharpness in the settings. Maybe, it's hard to say for sure, there
is a little back focus. By the way, this is with the 19-70 kit lens.

I'll do some research tomorrow to see if there is an actual bacfocus.

Anyone else with the same problem?

/erik

"Erik Persson" wrote in message
...
When I compare the pictures from my D70 and my PowerShopt G3 the G3
pictures seems very much sharper. This is the case even when I increase
the sharpness in the settings. Maybe, it's hard to say for sure, there
is a little back focus. By the way, this is with the 19-70 kit lens.

Are you shooting the same subject with both? Same aperture and shutter
speed? Tripod or handheld?
Any examples?

--
Colm

Colm wrote:
"Erik Persson" wrote in message
...

When I compare the pictures from my D70 and my PowerShopt G3 the G3
pictures seems very much sharper. This is the case even when I increase
the sharpness in the settings. Maybe, it's hard to say for sure, there
is a little back focus. By the way, this is with the 19-70 kit lens.


Are you shooting the same subject with both? Same aperture and shutter
speed? Tripod or handheld?
Any examples?


To be honest I haven't investigated it to that degree. It is more a of a
thing I've noticed when I compare pictures from the two cameras. I have
a large number of very crisp G3 pictures, and none of the D70 pictures
are as sharp. My feeling is that the use of a tripod does not make any
difference.

I'll put some examples on my webserver - will post the URL later.

/erik

I got the camera in august 2004 and it has (and had from the beginning)
the latest? (A 1.01 B 1.02) firmware. As I understand, it was a new
camera (they had to order it for me) and not something that had been in
the store for a long time.
Wasn't it the very first cameras that had the focus problem?
Did this problem persist until late summer 2004?

It could be that there is more in camera sharpening in the powershot,
but I can't see any halos on the photos.
The AF systems is different in campact and SLR digitals as far as I
know. The photos are all taken with AF so this _maybe_ could have some
impact - guessing here though...

I'll try to investigate this further and make my own focus test shart.

/erik

Ed Ruf wrote:

On Fri, 07 Jan 2005 06:59:57 +0100, in rec.photo.digital.slr-systems Erik
Persson wrote:


When I compare the pictures from my D70 and my PowerShopt G3 the G3
pictures seems very much sharper. This is the case even when I increase
the sharpness in the settings. Maybe, it's hard to say for sure, there
is a little back focus. By the way, this is with the 19-70 kit lens.

I'll do some research tomorrow to see if there is an actual bacfocus.

Anyone else with the same problem?


I believe there was a back focus issue with early models.
__________________________________________________ ______
Ed Ruf Lifetime AMA# 344007 )
See images taken with my CP-990/5700 & D70 at
http://EdwardGRuf.com

"Erik Persson" wrote in message
...
When I compare the pictures from my D70 and my PowerShopt G3 the G3
pictures seems very much sharper. This is the case even when I increase
the sharpness in the settings. Maybe, it's hard to say for sure, there
is a little back focus. By the way, this is with the 19-70 kit lens.

I'll do some research tomorrow to see if there is an actual bacfocus.

Anyone else with the same problem?

This guy claims to have a test for it. You might want to give it a try.

http://md.co.za/d70/chart.html#ActualChart

Thank you!
/erik

C J Campbell wrote:

This guy claims to have a test for it. You might want to give it a try.

http://md.co.za/d70/chart.html#ActualChart

On Fri, 7 Jan 2005 07:26:15 -0800, "C J Campbell"
wrote:


"Erik Persson" wrote in message
.. .
When I compare the pictures from my D70 and my PowerShopt G3 the G3
pictures seems very much sharper. This is the case even when I increase
the sharpness in the settings. Maybe, it's hard to say for sure, there
is a little back focus. By the way, this is with the 19-70 kit lens.

I'll do some research tomorrow to see if there is an actual bacfocus.

Anyone else with the same problem?

This guy claims to have a test for it. You might want to give it a try.

http://md.co.za/d70/chart.html#ActualChart

He only tests the center horizontal focusing sensor. Wouldn't it be
prudent to test each one separately?, there are 5 others.


--
Owamanga!

There is lens sharpness and digital sharpness.
You can compare manual to autofocusing on your own to see if the autofocus
is really the problem.
The D70 at default jpg settings seems to apply significantly less sharpening
than P&S and prosumer cameras and ramps up the contrast much less, all of
which affects apparent image sharpness. Also the physically very small
apertures in lenses used for smaller sensor cameras will tend to increase
depth of field and apparent sharpness regardless of the focal length of the
lens.
However, comparing raw images of the same subject from a Nikon D70 and a
Sony 828 I find there is an undeniable softness to the raw image coming off
the Nikon D70 compared to the Sony 828 that is not simply due to the
difference in megapixel count between the sensors, using the Adobe raw
plug-in for both cameras rather than the Nikon/Sony raw converters and
trying to use equivalent focal lengths and apertures.
I do not know if this is a sensor or software issue: it is possible that
in-camera processing is applied to the raw image differently in both
cameras.

Now I have done some tests comparing my G3 to my D70 with 18-70 kit
lens. The G3 lens is 35-140mm eqiv with aperture 2.0-3.0. The D70 18-70
is 3.5-4.5 with a 27-105 eqiv (1.5 crop factor). I compared the D70
(with the 18-70) to the G3 at the same aperture and at each cameras/lens
wide angle resp telephoto limit using a home made focusing chart. I used
a tripod.

At wide angle one of the objects on my test chart had a size of 65 mm on
the G3 and 70 mm on the D70 (roughly the same distance between the
sensors and the object). The D70 image was however very much larger in
the objects direction so the D70 picture thus corresponds to a smaller
focal distance. It is however of importance below when I compare the
resolution, since even though the objects on the G3 were smaller in
terms of number of pixels they occupied, the resolution and sharpness
seemed to be the same as with the D70!
I found the percieved sharpness about equal as well as the resolution
(that is, if a could tell 2 points apart in one of the pictures I could
do the same in the other). There was some sharpening artefacts in both
images and none were better than the other. The G3 had a larger DOF (but
you could take the G3 down to aperture 2.0 if you want a small DOF). The
D70 DOF was quite a bit back, but the object I focused on where in focus
(maybe there were a very slight back focus).
The G3 thus performed equally well as the D70 even though the objects on
the G3 was a little smaller (in of number of pixels).

At the telephoto limit one object where 233mm in the G3 and 191 mm in
D70. The G3 picture was virtually free from sharpening artefacts whereas
the D70 had some halos (I set the D70 sharpening to medium high). In
this test the resolution of the G3 was superior to the D70, possibly
because of the larger tele. I found the sharpness to be better in the G3
picture (but not by much) as well. In this test the D70 focused
accuratly with about equal DOF at both sides. Again, the G3 had a larger
DOF (but you could be set the aperture to 3.5 instead of the tested 4.5).

When it comes down to a pixel by pixel comparision, that is if a object
takes up the same number of pixels, the G3 seems superior. The G3 had no
problems with setting the correct focus (besides being much slower), but
D70 18-70 had some minor problems.
I have some problems explaining the larger DOF of the G3, especially
since it were more in the telephoto range, but I guess this is because
of the smaller optics that can be used secondarily to the smaller CCD.

There was some focusingproblems when using the D70 with the kit lens,
and the G3 seemed overall a little bit sharper (pixel by pixel), but I
can't say that this was because of bad focusing.

This test does not explain the differences I've seen before!

/erik

bmoag wrote:

There is lens sharpness and digital sharpness.
You can compare manual to autofocusing on your own to see if the autofocus
is really the problem.
The D70 at default jpg settings seems to apply significantly less sharpening
than P&S and prosumer cameras and ramps up the contrast much less, all of
which affects apparent image sharpness. Also the physically very small
apertures in lenses used for smaller sensor cameras will tend to increase
depth of field and apparent sharpness regardless of the focal length of the
lens.
However, comparing raw images of the same subject from a Nikon D70 and a
Sony 828 I find there is an undeniable softness to the raw image coming off
the Nikon D70 compared to the Sony 828 that is not simply due to the
difference in megapixel count between the sensors, using the Adobe raw
plug-in for both cameras rather than the Nikon/Sony raw converters and
trying to use equivalent focal lengths and apertures.
I do not know if this is a sensor or software issue: it is possible that
in-camera processing is applied to the raw image differently in both
cameras.