Meopta S2 & Xperia Z5 vs E-M1+MB+canon 400mm +Ext 1.4x III (1 Viewer)

I took some photos yesterday, on this owl I have as an avatar, with the E-M1 (16.3 Mpix effective, 4650 x 3500) & MB & canon 400mm EF USM & Ext 1.4 III and also, at the same distance, with my Meopta S2-scope with a Sony Xperia Z5 Compact (23 Mpix, 5520 x 4140).

At 30x-ish on the S2 I got 2590-ish pixels covering the owl vertically (measured, 62.5% of image vertically).

With the Oly camera I got only 1650-ish pixels vertically on the owl (measured, 47.2% of image vertically).

The sun was low, as it is this time of year, and there was small amount of fog in the air. Not ideal photography conditions.

Oly image data 16.1 MB RAW : crop factor 2, no digital zoom, ISO 2500, 1/100 s, f/8, 560 mm (1120 mm fullframe)

Digiscoped image data 5.78 MB jpg : crop factor 5.2, no digital zoom, ISO 250, 1/32 s, f/2, 4.23mm + plus scope body/FL 439mm & ocular 30-60x/FL 14.6-7.3mm ( ?? fullframe )

Attached are cropped jpg images of the head of the owl, first digiscoped image then the Oly image, for comparisons.....

/Anders

Very nice, Anders!

It confirms my experience that for stationary birds, digiscoping with small sensors is the way to go.
At 30x82, the exit pupil is 2.7 mm. The actual aperture of your Z5 is 2.1 mm, which means that the scope's exit pupil does not restrict the amount of light entering the camera. This means that you get the same exposure values as you would have without the scope (apart from minor transmission losses in the scope)

If a 50 mm focal length equivalent corresponds to 1:1 , 30x magnification means the FL equivalent is (30*50) = 1500 mm.
But your phone's camera has a lens with 25 mm FL equivalent, which means that the actual FL equivalent is (25/50)*1500 = 750 mm which is less than the Olympus's 1120 mm.

Not sure where you got the crop factor 5.2 from? My Z3+ (which I don't use for digiscoping) has a 20 MPix camera but the standard setting is only 8 MPix so I'm using camera apps like FV-5 and A Better Camera to get the 20 MPix as standard setting.

You should be able to zoom in to about 40x on the scope before exposure time increases, and easily 60x if you can manage the increased shake.
I'm using a small camera with 1/2.3" sensor and it handles the 75x DS on my Fieldscope very well. It is crucial to have the ocular lens and camera lens perfectly cleaned before shooting, though.

//L

Looksharp, thanks for your comments.

I got the crop factor from wikipedia...https://en.wikipedia.org/wiki/Crop_factor

The ISO numbers differs also affecting image quality...I used the scope on a tripod and leaned against a tree using the Oly/canon.

Sony says it has 8x digital zoom, and 5x clear zoom, what is that, is it an optical zoom?

Sony says it is a 25 mm main camera lens.....but exif data reads 4.23 mm when I take a photo without zooming in first.
When I zoom in 5x exif still reads 4.23mm when i take a photo....hmm...

In the Z5 you can choose 23 Mpix setting without special app.

Binoseeker said:

Looksharp, thanks for your comments.

I got the crop factor from wikipedia...https://en.wikipedia.org/wiki/Crop_factor

The ISO numbers differs also affecting image quality...I used the scope on a tripod and leaned against a tree using the Oly/canon.

Sony says it has 8x digital zoom, and 5x clear zoom, what is that, is it an optical zoom?

Sony says it is a 25 mm main camera lens.....but exif data reads 4.23 mm when I take a photo without zooming in first.
When I zoom in 5x exif still reads 4.23mm when i take a photo....hmm...

In the Z5 you can choose 23 Mpix setting without special app.

Click to expand...

When Sony claim it is a 25 mm lens, it means it has the equivalent focal length to a 25 mm wide angle lens with full frame sensor.
It is fixed, no optical zooms in any phone that I know of, so any zoom is digital/cropped.

I mentioned in my previous post that there is a significant difference in exposure value between a small sensor digiscoping setup and a more traditional
camera body + telephoto lens combo.
Thanks to the excellent light output through a big scope the ISO can be kept low with reasonably fast shutter times. This is why the results can be excellent despite the small sensor. That, and the long focal lengths.

The 60x setting on your scope would equal 1500 mm with your Z5, and you can/must crop it quite a bit too which means that the effective focal length equivalent is substantially longer.

//L

Right you are, L ...
Of course it is fullframe specification.

I did not get it together yesterday since wiki presents crop factor 5.2 and calculated crop factor is 25/4.23=5.9...to much of a difference.

One of my old kowa digiscoping holder for iphone 4/4s was to damaged in the plastic holder so i removed the metalic part and glued it on a plastic holder for the Z5, and filled in two gaps with black silicone to get it light proof s t s....so now i can use my Z5, nice.