A-200 Vignetting

dboogie said:

You can determine for yourself at which point the vignetting
unacceptable to you...as for me the vignetting doesn't really
bother me until it gets to 25.2mm.
Even then, a simple clone job can clear it up.

Click to expand...

Thanks for the samples. For that slight amount of vignetting I'd use the "dodge" tool to selectively lighten the area - it keeps the details vs replacing them with cloning.

Looking forward to giving the A-200 a full workout.

Hmmm, thanks for the tip Inigo. I've never used the "dodge" tool before (or burn for that matter). Now that you've suggested it, it gives me a reason to give it a try. I'm sure you'll like the A-200...I do.

dboogie
--

sometimes ya get what ya get and ya gotta be happy with what ya got........every photo can't be a masterpiece

Use a soft/fuzzy edged brush and a low percentage of "pressure" application to keep from overdoing it or showing edges. A pass or two at 10% or so should do the job there.

dboogie said:

Hmmm, thanks for the tip Inigo. I've never used the "dodge" tool
before (or burn for that matter). Now that you've suggested it, it
gives me a reason to give it a try. I'm sure you'll like the
A-200...I do.

dboogie
--
sometimes ya get what ya get and ya gotta be happy with what ya
got........every photo can't be a masterpiece

Click to expand...

I do enjoying to read comparisons like this , and i think that is time to bring up one of the oldest questions , does it really worth the price deference of the two teles !!

I do insist that it does not , but i like to listen your own lines on that question ..

Inigo Montoya said:

and based on a quick preliminary check, I'd say I've got around 30%
of the "zoom bar" range before vignetting sets in. (Digital zoom
DISABLED). And that's placing it in front of my UV "lens protector"
filter.

I also did a quick test comparing "actual" zoom compared to the Uzi
itself, and with the B-300 and got some "interesting" numbers.

I shot my kids' bunk bed at full wide, full zoom, full with the
A-200, and full with the B-300 and measured the distance between
two bolts on one of the posts in pixels (outside edge to outside
edge). Here were the numbers measuring the same image feature:

Wide - 35 pixels
Full zoom - 300 pixels - 8.57x over full wide
A200 full zoom - 417 pixels- 1.39x over full zoom
B300 full zoom - 451 pixels- 1.5x over full zoom

+ - 1 or 2 pixels for margin of error in my pixel measuring process.

A composite image of the latter 3 shots can be found here:

Full image: http://www.pbase.com/image/5863041



I suspect, but can't "prove" yet, that the presence of the step-up
ring for the B-300 is keeping it from being closer to its rated
1.7x.

Click to expand...

--



Olympus..C2100UZI+A200.1.5X_P-400..HP970Cxi=ZIO_USB..Sanyo1600 NiMh=Manfrotto 190DB+141RC
My mini gallery http://www.sigma-sa.com/kt/pelion/index.htm

'UZ'pShoot'ERS' said:

With my C-210 which vignettes at all tele positions. I've noticed
the vignetting lessend according to the Aperture opening size....I
think it's less with the smaller F/8 opening....Don't hold me to
that but try F/8 & then F/2.8 or lower if ya got it on the same
target & see if there's a difference....

Click to expand...

In my experience with the C-180 it's actually the opposite - vignetting is less at F3.5 (min at full zoom), and increases at higher aperttures, becoming very pronounced at F8 - a problem in bright sunlight, because if you try to minimize vignetting by setting a wide aperture, you may overexpose the photo.
--
Misha

dboogie said:

Hey w3, sorry for not getting back with this thread sooner.
I put the A200 on my UZi, went outside and took a few sample shots.
I disabled the digital zoom, so only optical zoom was utilized. The
settings for each shot was f3.5, 1/800 sec, ISO 100, white balance
auto, exposure compensation was set to -7 on each shot except the
29.8mm shot where it was 0 (i didn't realize I had changed it until
I pulled up the EXIF data). OTHER THAN DOWNSIZING FOR THE WEB, NO
OTHER EDITING (including cropping) WAS DONE ON ANY OF THE IMAGES.
Here are the samples:

70mm



29.8mm



27.3mm



25.2mm



You can determine for yourself at which point the vignetting
unacceptable to you...as for me the vignetting doesn't really
bother me until it gets to 25.2mm.
Even then, a simple clone job can clear it up. I hope this helps
you out.

dboogie

--
sometimes ya get what ya get and ya gotta be happy with what ya
got........every photo can't be a masterpiece

Click to expand...

--

sometimes ya get what ya get and ya gotta be happy with what ya got........every photo can't be a masterpiece

Thanks for the info and sorry for not responding sooner. Wanted to do some tests myself first before replying. Didn't have a chance to do the tests until yesterday.

Please try to do this. Shoot outdoor with Uzi/A-200 and aim at an off-white wall. Start from Full Tele, and zoom back out from the Full Tele position and stop at where you think vignetting starts or getting worse, take 4 or 5 pictures at those positions.

Use PhotoShop and open those pictures. Do an "Auto Levels" (Image-Adjust-Auto Levels) on each one of them. Now see if you notice where Vignetting starts.

With my Uzi/A-200 and test shots as decribed above, Vignetting starts at Full Tele !!!

dboogie said:

dboogie said:

Hey w3, sorry for not getting back with this thread sooner.
I put the A200 on my UZi, went outside and took a few sample shots.
I disabled the digital zoom, so only optical zoom was utilized. The
settings for each shot was f3.5, 1/800 sec, ISO 100, white balance
auto, exposure compensation was set to -7 on each shot except the
29.8mm shot where it was 0 (i didn't realize I had changed it until
I pulled up the EXIF data). OTHER THAN DOWNSIZING FOR THE WEB, NO
OTHER EDITING (including cropping) WAS DONE ON ANY OF THE IMAGES.
Here are the samples:

70mm



29.8mm



27.3mm



25.2mm



You can determine for yourself at which point the vignetting
unacceptable to you...as for me the vignetting doesn't really
bother me until it gets to 25.2mm.
Even then, a simple clone job can clear it up. I hope this helps
you out.

Click to expand...

Click to expand...

I couldn't find or download your full jpeg images. But from the downsized bmp images you posted and running the above described PhotoShop Auto Levels test, I definitely notiice Vignetting at 29.8mm and shorter lengths. I am not sure if I see anything at your Full Tele (70mm) though. Perhaps your images were not exactly off-white. They were more yellow and Auto Levels change them to greenish color and harder to tell.

Please try again outdoor at a lighter color/off-white wall and do the PhotoShop Auto Levels test on jpeg images. Let us know your observation. Other A-200 owners, pleast try as well. Thank you very much in advance.

dboogie said:

dboogie said:

dboogie

--
sometimes ya get what ya get and ya gotta be happy with what ya
got........every photo can't be a masterpiece

Click to expand...

Click to expand...

But should I be happy with a Tele Photo Lens that causes vignetting at Full Tele?

Soory to bring this to a more basic level, but..

I've been searching the forum in trying to find the best teleconverter for the UZI (C2100uz, I assume?): seems that the Olympus A-200 works well, but does it need the CLA-1 Lens Adapter Tube to mount it? It appears that the other one is the TCON 14B. Agian, will it mount directly or do you need a ring adopter? Also, is the A-200 called something else at B&H? a search using that turns up zero there. Please help a newbie.
Thanks

w3 said:

Thanks for the info and sorry for not responding sooner. Wanted to
do some tests myself first before replying. Didn't have a chance
to do the tests until yesterday.

Please try to do this. Shoot outdoor with Uzi/A-200 and aim at an
off-white wall. Start from Full Tele, and zoom back out from the
Full Tele position and stop at where you think vignetting starts or
getting worse, take 4 or 5 pictures at those positions.

Use PhotoShop and open those pictures. Do an "Auto Levels"
(Image-Adjust-Auto Levels) on each one of them. Now see if you
notice where Vignetting starts.

With my Uzi/A-200 and test shots as decribed above, Vignetting
starts at Full Tele !!!

Click to expand...

Rosty Caryk said:

Soory to bring this to a more basic level, but..
I've been searching the forum in trying to find the best
teleconverter for the UZI (C2100uz, I assume?): seems that the
Olympus A-200 works well, but does it need the CLA-1 Lens Adapter
Tube to mount it? It appears that the other one is the TCON 14B.
Agian, will it mount directly or do you need a ring adopter? Also,
is the A-200 called something else at B&H? a search using that
turns up zero there. Please help a newbie.

Click to expand...

A-200's got 49mm thread on the lens side and screws right onto the Uzi which has 49mm thread on its lens. No adaptor of any kind is needed.

Anyone else tried the PhotoShop Auto Levels test (described below) which seems to help detect vignetting? Please share.

Rosty Caryk said:

w3 said:

Thanks for the info and sorry for not responding sooner. Wanted to
do some tests myself first before replying. Didn't have a chance
to do the tests until yesterday.

Please try to do this. Shoot outdoor with Uzi/A-200 and aim at an
off-white wall. Start from Full Tele, and zoom back out from the
Full Tele position and stop at where you think vignetting starts or
getting worse, take 4 or 5 pictures at those positions.

Use PhotoShop and open those pictures. Do an "Auto Levels"
(Image-Adjust-Auto Levels) on each one of them. Now see if you
notice where Vignetting starts.

With my Uzi/A-200 and test shots as decribed above, Vignetting
starts at Full Tele !!!

Click to expand...

Click to expand...

I repeated the test outdoors in the afternoon, this time towards a brighter wall. Yesterday, the outdoor test shots were aimed at a wall in the shade and with the F-numbers at 3.5 and 2.8.

This time the F-numbers were all at 8.0.

Well, there was no vignetting at Full Tele (70mm).

None detected at 54mm either, even after running PhotoShop Auto Levels.

Aorund 37.4 or 39.3mm, vignetting can be detected after running the PhotoShop Auto Levels test to amplify the effect, but not quite visible otherwise.

At 29.8mm, vignetting can be detected without having to run the Auto Levels to amplify the effect.

The test results look better (less vignetting) than the ones the day before.

w3 said:

Please try to do this. Shoot outdoor with Uzi/A-200 and aim at an
off-white wall. Start from Full Tele, and zoom back out from the
Full Tele position and stop at where you think vignetting starts or
getting worse, take 4 or 5 pictures at those positions.

Use PhotoShop and open those pictures. Do an "Auto Levels"
(Image-Adjust-Auto Levels) on each one of them. Now see if you
notice where Vignetting starts.

With my Uzi/A-200 and test shots as decribed above, Vignetting
starts at Full Tele !!!

I couldn't find or download your full jpeg images. But from the
downsized bmp images you posted and running the above described
PhotoShop Auto Levels test, I definitely notiice Vignetting at
29.8mm and shorter lengths. I am not sure if I see anything at
your Full Tele (70mm) though. Perhaps your images were not exactly
off-white. They were more yellow and Auto Levels change them to
greenish color and harder to tell.

Please try again outdoor at a lighter color/off-white wall and do
the PhotoShop Auto Levels test on jpeg images. Let us know your
observation. Other A-200 owners, pleast try as well. Thank you
very much in advance.

w3 said:

w3 said:

dboogie

--
sometimes ya get what ya get and ya gotta be happy with what ya
got........every photo can't be a masterpiece

Click to expand...

Click to expand...

But should I be happy with a Tele Photo Lens that causes vignetting
at Full Tele?

Click to expand...

Thanks, w3. Appreciate the help. Am off to buy one.

w3 said:

Rosty Caryk said:

Soory to bring this to a more basic level, but..
I've been searching the forum in trying to find the best
teleconverter for the UZI (C2100uz, I assume?): seems that the
Olympus A-200 works well, but does it need the CLA-1 Lens Adapter
Tube to mount it? It appears that the other one is the TCON 14B.
Agian, will it mount directly or do you need a ring adopter? Also,
is the A-200 called something else at B&H? a search using that
turns up zero there. Please help a newbie.

Click to expand...

A-200's got 49mm thread on the lens side and screws right onto the
Uzi which has 49mm thread on its lens. No adaptor of any kind is
needed.

Anyone else tried the PhotoShop Auto Levels test (described below)
which seems to help detect vignetting? Please share.

w3 said:

w3 said:

Thanks for the info and sorry for not responding sooner. Wanted to
do some tests myself first before replying. Didn't have a chance
to do the tests until yesterday.

Please try to do this. Shoot outdoor with Uzi/A-200 and aim at an
off-white wall. Start from Full Tele, and zoom back out from the
Full Tele position and stop at where you think vignetting starts or
getting worse, take 4 or 5 pictures at those positions.

Use PhotoShop and open those pictures. Do an "Auto Levels"
(Image-Adjust-Auto Levels) on each one of them. Now see if you
notice where Vignetting starts.

With my Uzi/A-200 and test shots as decribed above, Vignetting
starts at Full Tele !!!

Click to expand...

Click to expand...

Click to expand...

'UZ'pShoot'ERS' said:

With my C-210 which vignettes at all tele positions. I've noticed
the vignetting lessend according to the Aperture opening size....I
think it's less with the smaller F/8 opening....Don't hold me to
that but try F/8 & then F/2.8 or lower if ya got it on the same
target & see if there's a difference....

Click to expand...

1. At first I tested by only observing through the EVF LCD and also like you said on the SAME TARGET (at about the same time) and didn't see much difference.

2. Now, I tried A-200/Uzi outdoors at a wall IN THE SHADE with F3.5 to F2.8 and tried to observe vignetting from the resulting images at all positions:

a. Detect vignetting at full tele (70mm camera focal length, F3.5) after, and ONLY after, using PhotoShop Auto Levels to amplify the effect

b. Detect vignetting at 41.3mm (F2.8) if examining the image carefully, even without PhotoShop Auto Levels to amplify the effect

c. Easily see vignetting at 29.8mm (F2.8)

3. And then the next day I tried it at a BRIGHTER wall (NOT THE SAME TARGET) in the sun (a different time) with a smaller aperture F8 and got better results:

a. Detect vignetting at about 39.3 or 37.4mm camera focal lengths (F8) after, and ONLY after, using PhotoShop Auto Levels to amplify the effect

b. Detect vignetting at 29.8mm (F8) if examining the image carefully, even without PhotoShop Auto Levels to amplify the effect.

c. Easily see vignetting at other focal lengths (F8) shorter than 29.8mm.

4. Last night, I tried Uzi/A-200 indoors under dim incandescent lighting without flash:

a. No vignetting at 70mm (F3.2)

b. Detect vignetting at 61.0mm (F3.2) if looking for it, or after using PhotoShop Auto Levels to amplify the effect.

c. Dectect vignetting at 57.3mm (F3.2), even without using PhotoShop Auto Levels to amplify the effect.

d. Easily see vignetting at 51mm (F3.2)

Focal Length values above are for indication of Zoom positions, are the actual values (not 35mm equiv) and of the camera itself (without multiplying the Zoom Lens effect).

Are all these test results in line with other A-200s out there?

It seems to me that how much vignetting we will observe may be more related to Brightness/Exposure of the images than to F numbers. Any opinions?

I remember when I was at the camera shop testing another A-200 on Uzi previously, I was pointing at the door or near the front window area which was brighter and perhaps therefore observing less vignetting and more usable Zoom range.

By the way, the bar scale in EVF LCD and the Zoom Lever may be on some Log/Exponential scale. When it was near the full tele position (longer focal length), a tiny zoom move (shown also as a tiny bar scale move) represents a big CHANGE in camera focal length; and when it was near full wide, a tiny move is a tiny change - perhaps percentage wise the change was about the same.

misha said:

'UZ'pShoot'ERS' said:

With my C-210 which vignettes at all tele positions. I've noticed
the vignetting lessend according to the Aperture opening size....I
think it's less with the smaller F/8 opening....Don't hold me to
that but try F/8 & then F/2.8 or lower if ya got it on the same
target & see if there's a difference....

Click to expand...

Click to expand...

Member said:

In my experience with the C-180 it's actually the opposite -
vignetting is less at F3.5 (min at full zoom), and increases at
higher aperttures, becoming very pronounced at F8 - a problem in
bright sunlight, because if you try to minimize vignetting by
setting a wide aperture, you may overexpose the photo.
--
Misha

Click to expand...

I don't know what to say.

Maybe you got an overall brighter image at F3.5 than you did at F8. At F8, you may dim the image more and too much. And if it is a sunny enough day, even at F8, your images will come out fine with less vignetting. There is a point where you can open up the aperture enough to minimize vignetting without overexposing.

It may not be F number related. It may be related to the Brightness of the image. The brighter (but not overexposed) the overall image, the less vignetting. So it seems. Please check my 10/20/02 post below.