Vignetting at maximum zoom HV40

[maclegrio]

when i use my HV40 on a sunny day i discovered very distinct shadowing in the corners and lateral sides in strong telezoom and maximum when the background is blue homogen sky.
it is most obvious on the LCD of the computer.
It is disturbing when making movies with surfers or animals when the sky comes into background.
it bcomes more distinct when closing the aperture (=higher value)
I can reproduce it on sunny days.

It occurs without any additional lenses and without or with lensehood.

It does not occur at wide angle and medium zoom.

I have no explanation why this happens.
I would like to know if this shadowing at maximum zoom occurs in other HV20, 30 or 40 too. So please try it against blue light sky and tell me what u see.
Thank you very much in advance!

[Janke]

Yes, I see it too, but it's not very distracting. The enclosed screen grab shows it.

"It's not a bug, it's a feature..."

[Seo]

All lenses vignette. You can try correcting it in post if it's really distracting.

[maclegrio]

Thank u for replies!

Yes, I see it too, but it's not very distracting. The enclosed screen grab shows it.

"It's not a bug, it's a feature..."

Its the more obvious, the brighter the day is.

and as these shadows move when zooming in, it can be distracting

I found a movie on Youtube where i see vignetting in telezoom just as it happens in my camera.
[nomedia="http://www.youtube.com/watch?v=db1Z2BMosgw&feature=related"]YouTube- Canon HV30 high definition film look[/nomedia]

Watch the scene with the helicopter, when its zoomed in.(start at 2:49)

[maclegrio]

Now i managed to upload an original picture from my footage.

it is distorted but it shows the important things. This footage was shot at maximum zoom, You see diffuse vignetting at the upper corners and lateral sides. Its more distinct in the movie than on the still picture.

[Janke]

Not surprising at all, pretty good actually - what do you really expect from a 20x zoom in a $1,000 camera?

A 10x zoom for a professional movie camera can cost more than $10,000...

[Khaver]

This discoloration (discolouration for the Europeans) is also caused by chromatic abberation. Zoom lenses have more glass in them than a prime and the tele setting brings this out. There are some plugins for virtualdub and avisynth that allow you to compensate for it a little and it can help in reducing the discoloration. There may be plugings for NLE's also. Google is your friend.

[maclegrio]

Not surprising at all, pretty good actually - what do you really expect from a 20x zoom in a $1,000 camera?

A 10x zoom for a professional movie camera can cost more than $10,000...

20x..? Sorry i forgot to say that i only used the optical zoom of the camera which goes up to 10X.

by the way; when you read about vignetting then nearly everybody talks about vignetting in wide_angle and nearly nobody talks about vignetting in maximum zoom.
the very few cases with vignetting in telezoom tend to suspect a bug in the construction of the zoom.
I never happened to know vignetting at maximum zoom in other cameras.

what i want to rule out if i have to live with it or is it reasonable to send the camera to a service.

As there are many users of HV 20 ,30,40 i would like to know if many see this vignetting at maximum zoom on bright days.

[cgbier]

Yes, it is there.

[Janke]

20x..? Sorry i forgot to say that i only used the optical zoom of the camera which goes up to 10X.

Uh, that was a typo - I was comparing 10x to 10x actually...

Yes, it's there, forever - as I said, it's not a bug, it's a feature... so you'll just have to learn to live with it!

[Khaver]

To continue my chromatic abberation post, blue light refracts through glass a different amount than other colors. This is why the blue sky gets that violet hue around the edges of the frame. Blue blocker sunglasses exploit this by filtering out the blue light, thus making the view through the glasses sharper.

As others said, there's not much you can do except try to fix it in post if it bothers you too much.

[maclegrio]

well thanks a lot for helping. i purchased the camera a month before and it was really striking for me when i watched the footage taken on a sunny day.
may be the degree varies in some editions.

Please all, who are reading this:
post
wether you see the vignetting at maximum zoom or not.

To continue my chromatic abberation post, blue light refracts through glass a different amount than other colors. This is why the blue sky gets that violet hue around the edges of the frame. Blue blocker sunglasses exploit this by filtering out the blue light, thus making the view through the glasses sharper.

As others said, there's not much you can do except try to fix it in post if it bothers you too much.

Under chromatic aberration i understand the differnt colours along the border of an an imaged object. which this camera does not seem to show at all.

by the way this vignetting can also be seen against light white surfaces.

[cgbier]

Under chromatic aberration i understand the differnt colours along the border of an an imaged object. which this camera does not seem to show at all.

C/A is mostly seen in high contrast areas (see Khaver's comment). In "day to day" situations it is there, but not as visible.
Problem is that visible light consists of a rather wide range of wavelengths. Basically each wavelength has its own focus point. The longer a lens, the more it shows. Lenses have to be built to a kind of "one size fits all". The engineers have to choose, which side of the color spectrum they have concentrate on more. They choose to neglect blue. A remedy is to use APO glass. This costs a bit though. It is not always wise to put it into a consumer cam that has be sold for a competitive price (and weight).
The HV lens isn't that bad. I assume it is a tele-Tessar. It is very hard to implement an APO'ed element into this design.

[maclegrio]

Well i doubt that chromatic aberration can produce such a broad area of hue; in my case i see a relatively large area of dark. and on pictures with high contrasts i dont see chromatic aberration. it is striking because on the movie you see it really fast moving from the periphery towards the center of the image, while zooming in an i seems to change size with move of the iris. maybe also image stabilizer.

I have a sony camcorder ( hi8 800 E) (2500 $) with 10x zoom. It has no vignetting at all but on pictures with high contrasts one could see well this chromatic aberration.
i have another cheap canon hi8 camera (200$) wich also does not show this vignetting.

[kakomu]

by the way; when you read about vignetting then nearly everybody talks about vignetting in wide_angle and nearly nobody talks about vignetting in maximum zoom.
the very few cases with vignetting in telezoom tend to suspect a bug in the construction of the zoom.
I never happened to know vignetting at maximum zoom in other cameras

Vignetting most certainly occurs on the long end of many zooms. The larger the zoom ratio/magnification, the greater chance of vignetting.

It's most readily apparent with bright, featureless backdrops (e.g. a cloudless sky). It becomes far less apparent when the backdrop has features of varying color and luminance. I've encountered vignetting many times when photographing far off subjects against the sky.

Moral of the story? Learn the camera's weaknesses and work around them.

[cgbier]

I have a sony camcorder ( hi8 800 E) (2500 $) with 10x zoom. It has no vignetting at all but on pictures with high contrasts one could see well this chromatic aberration.
i have another cheap canon hi8 camera (200$) wich also does not show this vignetting.

Those cameras have a much lower resolution, so optical flaws will not show that much (but are there). And I assume that your cheap Canon has a small sensor, so the lens doesn't have to do that much magic to cover the rather large imager of the HV.
The more resolving power or magnification you have to pack in a small, cheap lens, the more optical flaws you build in.