PDA

View Full Version : Digiscoping initial results with Canon Powershot S5 IS


birdsofvirginia
Monday 28th January 2008, 05:56
Last month while on vacation I decided to purchase a small, portable point-and-shoot camera to tote around inside Universal Studios Florida that hopefully would produce decent images. (I didn't want to haul around my considerably more expensive Canon 5D setup.) Luckily I was able to try out several models and quickly decided on the Canon Powershot S5 IS. The first day of use, it was bright overcast with rain squalls throughtout the day and this little camera produced some impressive outdoor images throughout the day and into the night.

From time-to-time I still have a go at digiscoping with my old Nikon Coolpix 990, especially for documenting distant rarities. However it has begun to fail and the fact remains, it is extremely slow writing to card. The Canon Powershot S5 IS is certainly a much faster camera and although the lens opening is considerably larger than that of the CP 990/4500 which typically does not make it a good match for digiscoping. I figured it wouldn't hurt to give it a try.

I have a Kowa Prominar 823M spotting scope with the Kowa DA1 ditigal camera adapter primarily used with 32mm wide angle eyepiece. For the Powershot I purchased the Lensmate adapter and Kowa's step-up ring and today I headed out to try it out.

First, I was somewhat surprised at how relatively easy the powershot was to work with! About the only difficult thing for me was using the scope to focus on the moving subjects. The Powershot S5 allows you to quickly and easily switch to movie mode and snap a picture during the recording, a great feature for capturing moving/flying subjects.

Change in lighting conditions as you shoot? No problem. Shutter speed and aperature value can be quickly changed by simply pressing a button!

Attached is sample result from my first digiscoping attempt with the Canon Powershot S5 IS. I shot in either Manual or Av mode, macro setting (NOT supermacro). There was some vignetting but can easily be cropped.

The two attached samples are same image - (original,resized to 600x440 and cropped/sharpened) - no adjustments made to color, contrast, etc.

Image #1: Gadwall-600x440 - subject approximately 77-83 yards away (measured with laserfinder)
Shooting Date/Time 1/27/2008
Shooting Mode Manual
My Colors Mode Off
Tv (Shutter Speed) 1/640
Av (Aperture Value) 3.2
Light Metering Center Weighted Avg.
ISO Speed 100
Lens 6.0 - 72.0 mm
Focal Length 6.0 mm
Digital Zoom x 2.0
IS Mode On
Image Size 3264x2448
Image Quality Superfine
Flash Off
White Balance Day Light
AF Mode Continuous AF
Parameters Contrast Normal
Sharpness Normal
Saturation Normal
Color Space sRGB
File Size 1982 KB
Drive Mode Single-frame shooting


Image 2: Gadwall-sharpened
Zoomed to 100%, cropped and resized

ostling41
Monday 28th January 2008, 07:23
Your camera has a 36-432mm (equivalent) zoom, and you shot the gadwalls using the widest setting. Would you not get less vignetting, or eliminate it, if you shot longer?

Also, you are using 2X digital zoom (which is merely an image crop), and you are subsequently cropping the results even more to cut out the vignetting. Something seems amiss, with this approach.

birdsofvirginia
Monday 28th January 2008, 14:59
I tried shooting long by zooming in and although subject was larger whereby I could read a metal leg band in bright sunlight, there was noticeably more vignetting. I need to check the "2X digital" zoom setting which is either a default OR result of the "Macro" setting.

Also, when I attempted to shoot at full range (zooming all the way), the camera locked up and "lens error, need to restart" error message popped up.

Is it possible small amount of vignetting is result of using wide angle eyepiece instead of the 20-60mm zoom? Ah, more field testing....



--------------
Brenda
Digital Nature Photography
www.birdsofvirginia.com

birdsofvirginia
Monday 28th January 2008, 20:27
Followup to 2x digital zoom. This appears to be the default and not result of using "macro" setting. I went though images taken yesterday and have attached one that was taken using continuous autofocus and macro NOT turned on: Image of Eurasian Wigeon (original @600x440 and zoomed 100% and cropped)

Camera Model Name Canon PowerShot S5 IS
Shooting Date/Time 1/27/2008 4:35:16 PM
Shooting Mode Manual
My Colors Mode Off
Tv (Shutter Speed) 1/500
Av (Aperture Value) 2.7
Light Metering Center Weighted Avg.
ISO Speed 100
Lens 6.0 - 72.0 mm
Focal Length 6.0 mm
Digital Zoom x 2.0
IS Mode On
Image Size 3264x2448
Image Quality Superfine
Flash Off
White Balance Day Light
AF Mode Continuous AFParameters Contrast Normal
Sharpness Normal
Saturation Normal
Color Space sRGB
File Size 2113 KB
Drive Mode Single-frame shooting

JGobeil
Monday 28th January 2008, 22:02
Brenda,

Regarding the photos of the Wigeon of your last post. Is the vignetting we see on the first picture the only vignetting you got or did you remove some by cropping ?

Also, why use the minimum lens zoom and add a numeric zoom. Is this how you achieve minimal vignetting ?

birdsofvirginia
Monday 28th January 2008, 22:43
The first image of the wigeon is the "original" without any cropping or other mondificaitons except to resize to 600x440. The amount of vignetting appears to same for all of the images taken yesterday without zooming out (shooting long).

The second image I cropped out a good portion.

So far I have been able to crop out the corners and still have good portion of image remaining to work with.

-------------
Brenda

JGobeil
Monday 28th January 2008, 22:49
Interesting. Thanks for the info Brenda, I'll give it a try with my S2IS.

Neil
Tuesday 29th January 2008, 00:49
If this lens behaves like the G6 lens you get minimal vignetting at wide but as soon as you zoom the lens retracts like mad into the camera body and the vignetting gets worse until you get back to almost full zoom.
This camera might work with the Kowa Video eyepiece which has 57 mm of eye relief , although it's angle of view might not be enough.
Interesting results, Neil.

Silverback
Thursday 21st February 2008, 04:19
Brenda,

I too am the proud owner of an S5 and although I am sure that by now you have discovered how to change it, you can set the default of the digital zoom by accessing the menu (push the menu button while you are in the shooting mode and you'll find that it is the second item down). Good luck with the digiscope!