Pages: 1 [2]   Go Down

Author Topic: They just don't get it!  (Read 9707 times)

Ken Bennett

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1634
    • http://www.kenbennettphoto.com
Re: They just don't get it!
« Reply #21 on: April 04, 2013, 09:44:41 AM »

Some people here seemed to have mis-read what you are hoping for, given all the recommendations of prime lenses ("Fuji and the 35/1.4 normal lens"),


Guilty. I read too quickly and thought he said "normal lens" -- missed the "zoom" part. Mea culpa.
Logged
Equipment: a camera and some lenses. Images: Work photos. Personal photos.

BJL

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 5665

I looked at the photozone review of this lens.  A direct quote from their review:

That said it is still interesting to look a bit behind the scenes by using an "unsupported" RAW converter like e.g. RAW Therapee. This converter reveals the native barrel distortion level of about 5.8% at 12mm. This is excessive ...
Which suggests that the lens should be used according to the manufacturer's instructions. mFT lens compactness is achieved in part by handling distortion with software correction in addition to "hardware" correction, with the manufacturers' stated intention being to the apply software distortion correction: either in-camera, or with the provided RAW conversion software, or in software like Lightroom or ACR, which can do it using the lens profile information that Olympus and Panasonic include in their raw files. Photozone seems aware of the latter, by its use of a non-mainstream converter specifically to avoid those corrections.

As to this:
Quote
... in-camera correction comes with its own problems when the image is stretched and/or compressed to remove barrel and pincushion distortion.
to the extent that this is a problem, one should measure and assess the degree of _that_ problem, by looking at files that have been converted in the intended way, with correction. Otherwise, what photozone says is a bit like complaining about food poisoning after ignoring the label warning people not to eat something raw.
Logged

ErikKaffehr

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 10043
    • Echophoto

Hi,

I think it is quite OK to fix correctable problems in software. Hasselblad also does it. Vendors should publish data for automatic control of distortion. I don't know if Sigma does this, but they supply correction tables for all their lenses to Adobe. This can be be done at the design level.

Best regards
Erik


Which suggests that the lens should be used according to the manufacturer's instructions. mFT lens compactness is achieved in part by handling distortion with software correction in addition to "hardware" correction, with the manufacturers' stated intention being to the apply software distortion correction: either in-camera, or with the provided RAW conversion software, or in software like Lightroom or ACR, which can do it using the lens profile information that Olympus and Panasonic include in their raw files. Photozone seems aware of the latter, by its use of a non-mainstream converter specifically to avoid those corrections.

As to this:to the extent that this is a problem, one should measure and assess the degree of _that_ problem, by looking at files that have been converted in the intended way, with correction. Otherwise, what photozone says is a bit like complaining about food poisoning after ignoring the label warning people not to eat something raw.

BJL

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 5665
m4/3 lens correction profiles are "published", sort of: in the raw files
« Reply #24 on: April 05, 2013, 07:11:26 PM »

Vendors should publish data for automatic control of distortion. I don't know if Sigma does this, but they supply correction tables for all their lenses to Adobe.
From what I have read, Olympus and Panasonic "publish" this information for Micro Four Thirds lenses in a sense: this data is included in the raw file in a format that at least Adobe knows how to use, which is why Adobe can do distortion correction in Lightroom and ACR without having any profiles listed for any Olympus or Panasonic lenses. Note the strange absence of those two brands from the list of lens profiles, which on the other hand has profiles for every other significant lens brand, and even multiple iPhone models:
http://helpx.adobe.com/x-productkb/multi/lens-profile-support-lightroom-4.html

I not know if this is also done with third party m4/3 lenses like those from Sigma: ideally this would be part of the m4/3 standard and a requirement for m4/3 badging of a lens.
Logged

IanBrowne

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 91
Re: They just don't get it!
« Reply #25 on: April 08, 2013, 12:29:47 AM »

Not sure what you term as a small camera Marc but I recently bought a Panasonic FZ 200 with a consistent F2.8 from 25mm to 600mm! Certainly not a pocket camera but I have been surprised to how good it is. I'm really surprised at the image quality I can get from it. But my favourite camera is the Canon G12. I don't print many photos these days but I would have no drama ordering up to a 12 x 18 inch photos from either camera.  The poor 5D11 does not get to go on too many walks these days  :'(.
Logged
Pages: 1 [2]   Go Up