Observation & request for others (sx230, etc) experience- *image seen from raw* - RAW Shooting and Processing - CHDK Forum  

Observation & request for others (sx230, etc) experience- *image seen from raw*

  • 5 Replies

I have been testing the sx260hs CHDK port, beta, and was a bit surprised by the 'image' I got from within the DNG.

The image from a sx40 file I have was essentially a 'centered' sensor view of the lens and was symmetrical, as though looking thru a lens with he expected inside barrel and 'vignetting' in the corners, ie a rectangle in a circle.

With the sx260 (or at least mine),  I am getting an 'offset' rectangle in a circle with the left side much like the sx40 'view', but the right hand side is essentially square, with only a touch of corner vignetting, as though the sensor is de-centered rightward.

Any others see this type of 'de-centered' rectangle in circle from their DNG files??


PS: I am very pleased with the results of the DNG files, I am using LR v3.4 & LR v4.0 to process.


Offline philmoz

  • *****
  • 3450
    • Photos
The active area of the sensor is probably not set correctly so you may be seeing unused portions of the sensor. Often these unused areas are not symmetrical around the edges.

CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)


Offline Pier

  • ***
  • 128
The block of lenses of SX130 IS viewed from CCD side.You can see screws, with which is attached the sensor (maybe there is another one screw under the bandcable) and glue fixing the screws.Maybe there is the problem... during the adjusment.
« Last Edit: 06 / May / 2012, 02:28:23 by Pier »


Offline asm1989

  • *****
  • 527
  • SX720, SX260, SX210 & SX200
Can you post an example, using sx260 I see the barrel distortion left & right with no zoom like in other cams with extended picture area compared with the jpg, but looks centered if you compare it with the jpg

Upper side left & right barrel with no zoom, in the lower side is like 2 o 3 time less distotion

Once you take 2 o 3 zoom steps the barrel almost disappears in the raw file,

« Last Edit: 06 / May / 2012, 04:52:28 by asm1989 »

I am not really referring to lens barrel distortion but just the fact that comparing to a sx40 (24mm equiv) DNG & my DNG's (25mm equiv) that 'my' vignetting and 'view' of the inside of the lens 'barrel' is NOT symmetrical as is the sx40 DNG.

I realize I am seeing the inside of the lens components but was surprised to see it NOT perfectly centered within the 'barrel' of the lens (cropped out for jpegs).

I have noted that some ppl have seen 'asymmetrical' lens (one side is more blurred/less sharp than the other) on various cameras including a sx260 & sx40 & others, wonder if this explains why it is offset to achieve the best result?

I have not seen fuzzy sides either in the DNG's or jpegs from this camera, just the above asymmetrical 'observation'.

I ashamedly returned my sx260 & bought another one from a different seller, the new one has a nearly perfectly 'centered' sensor, ie 'rectangle is centered in the circle'. Lens does not seem any sharper, DNG or jpeg, but this is after very little testing/shots.

PS: I found a sx230hs lens correction for Lightroom, and it works very well at correcting vignetting & barrel distortion (at 25mm eq) and keeping most of the actual lens capability, which is cropped off by in-camera jpegs!!! Impressed!!
« Last Edit: 06 / May / 2012, 22:26:59 by StealthTaffer »


Forgot to mention that is a cool picture, I have never seen a P&S sensor assembly, DSLR's I have, good to see what it actually may look like inside a sx260 & similar Canon P&S's!



Related Topics