Yashica EZ F521 - digital Holga - RAW shooting and hidden menu

Started Jul 8, 2010 | Discussions thread
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Oertling New Member • Posts: 11
Yashica EZ F521 - digital Holga - RAW shooting and hidden menu
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Hi all,

Anyone interested in the Yashica EZ F521, sometime dubbed the 'digital Holga', might be interested in the hidden menu which, amongst other things has a RAW snapshot option.

Yes, that's right. The digital Holga, which people have been modding to increase vignetting and to make it softer/more blurry just like the real thing can shoot in RAW mode! Bit of a contradiction surely...?

Here's what you do to get to the hidden menu:

1. switch off F521
2. turn lens to macro position
3. hold down the shutter button - keep it pressed down!
4. turn on the F521 - while keeping your finger on the shutter button.

5. let go of the power button - while keeping your finger on the shutter button.

6. after about 4 seconds the hidden menu appears with "USB power mode" as the top option.

The hidden menu has the following options:

  • USB power mode

  • Configure ->

  • Snap Raw

  • Pv Raw

  • Pv YUV

  • FW UPDATE

  • AE Test ->

  • OB Calibration

  • PV OB Mode

  • AWB Test

  • BadPixel

  • AWB CLIB

The configure menu has the following options:

  • OB

  • Lens shading

  • Gamma

  • AE

  • AE Gid + -

  • AWB

A lot of the options are quite clear (FW UPDATE for example) but I don't know what OB is.

When you switch off the camera the ByeBye text now has a blue line round it - cute.

You can take a RAW pic by selecting the Snap Raw option, which immediately takes a picture and stores it on the memory card with the extension .RAW and with a file size of 3,781KB.

The RAW files are 8-bit grey Bayer pattern files so you need to de-Bayer them. I first tried Irfanview (selecting 8-bit per pixel, GB for the Bayer pattern start, and choosing picture size of 2272 by 1704 pixels). 2272 by 1704 means the RAW file is 3.9megapixels rather than the 5MP touted as the camera's resolution. Someone telling a little white lie in the advertising?

Irfanview does a fair job but leaves some Bayer artifacts. So next I tried Photoshop Elements 3.0 (old, but works fine for most things!) which imported the file as the grey Bayer pattern. I then saved this as a TIF and loaded into MATLAB and used the "demosaic(I,'gbrg')" command to de-bayer the image. I then saved this as a TIF. A bit unusual, but it was quick and it worked well.

Here are a couple of example:

1. 100% crop of RAW file (3.9MP)

2. 100% crop of highest quality, highest resolution (12MP interpolated) JPEG

3. 100% crop of RAW after it has been scaled to the same size as the 12MP JPEG above (4000x3000)

The RAW file is certainly smoother and without JPEG artifacts. It also (when scaled to 12MP) seems to contain as much information as the 12MP JPEG, suggesting that the camera might even have 3.9MP native resolution rather then 5.0 as advertised. Clearly the RAW images can undergo some contrast adjustment and sharpening to bring out the image. The Japanese writing on the yellow sign can me made to stand out like the JPEG version.

All this is a bit academic, but I take a perverse delight in finding RAW capabilites, however limited, on a $50 toy camera.

I hope other owners of the F521 will want to explore the hidden menu and tell me what everything means and how to use it. There is a slight chance that an exposure compensation can be set here so that the camera doesn't forget it everytime it is switched off - a complaint by some owners. Shame there's no option to turn off the beeper.

[of course the above is for information only - I do not recommend any of it - if you brick your camera it won't be my fault!]

Cheers,
Jonathan

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