What is the crop factor for Canon EOS 77D with Sigma 8mm F:3,5?

[t...@tbt.no]

What is the crop factor for Canon EOS 77D with Sigma 8mm F:3,5?

Just upgraded from Canon EOS 760D to Canon EOS 77D.

Now there is a  black hole in zenith and a large hole in nadir on all stitched Google Street View panoramas. The zenith hole generates a lot of wasted time patching the images. The nadir hole is very large.

The hole in nadir is much wider that there was when using the same lens with EOS 760D.

When using 760D, there was no hole in the zenith.

When opening photos the dialog as shown in this link  displays:

http://tinyurl.com/yd87cenq

When choosing "Presets: Digital SLR" these values are filled:

Crop factor / focal length multiplier: 1,5

(or the size of the image sensor: 16x24 mm)

These values are probably wrong.

What is the correct value?

[Keith Martin]

On 8 Jan 2018, at 12:44, tbt via PTGui Support wrote:

> The hole in nadir is much wider that there was when using the same
> lens with EOS 760D.

Both the Canon 760D and 77D are crop-sensor models. I believe the Canon
multiplication factor is 1.6 rather than 1.5, but that wouldn't explain
the zenith and nadir hole size discrepancy. In fact, at the basic level,
the same details should work for both cameras. Can you tell us your
workflow steps?

k

[John Houghton]

On Monday, January 8, 2018 at 12:44:38 PM UTC, t...@tbt.no wrote:

What is the crop factor for Canon EOS 77D with Sigma 8mm F:3,5?

The crop factor is the same as for the 760D (the sensor sizes are identical).

Check that the lens is specified as a circular fisheye on the Lens Settings tab, and set the crop circle on the edge of the image circle on the Crop tab. 

John

[t...@tbt.no]

Workflow steps:

1.

Import the RAW files to LightRoom

2.

Applying Camera Calibration Profile generated with X-Rite ColorChecker Passport.

Setting white balance.

3.

Menu:

"Edit Photo with PTGui Pro"

"Edit a Copy with Lightroom Adjustments"

File Format: TIFF - Color Space: sRGB - Bit Depth: 16 bits/component - Resolution: 300 - Compression: None

4.

Camera / lens data (EXIF)

Choosing "Presets: Digital SLR"

[t...@tbt.no]

Thank you for your help.

Using:

"Crop factor / focal length multiplier: 1,59"

seems to solve the problem.