Latest or all posts or last 15, 30, 90 or 180 days.
Welcome to diglloyd.com
In-depth review coverage is by subscription.
Also by Lloyd: MacPerformanceGuide.com and WindInMyFace.com
First-time visitor
Up to 1527MB/s sustained performance
🌈Shooting in Mountains thru ~Oct 27
I descend for internet service each day *when feasible*, but not always. Please be patient when subscribing. Hiking injured knee but cycling is therapeutic.

Sony A7R: Sensor Glass Thickness, Ray Angle and Image Degradation: Kolarivision Modification

Just arrived from Kolarivision is a Sony A7R in which the sensor cover glass has been replaced with significantly less thick glass. See A Thinner Sensor Stack at LensRentals.com for some background info.

I’ll be shooting this modified camera this weekend, with a report to follow.

The thick sensor cover glass has meant that rangefinder lenses (Leica M, Zeiss ZM, Voigtlander) have had severely degraded performance outside (roughly) the central 1/2 of the frame, due to ray angle, as reported on for years, and documented extensively on this site.

General issues from sensor glass

From Astigmatism and Digital Sensors in Making Sharp Images. Here, “glass plate” means the sensor cover glass.

  • The main impact of an added glass plate to more oblique rays is the introduction of severe astigmatism in the imaging field. The tangential image surface is shifted forward while the sagittal is minimally affected.
  • Astigmatism means a highly non-symmetric point image, not just being softer but killing the similarity between object and image structures. Often the blur resembles the effects of motion blur which can produce “cross-eyed” or double-image bokeh (very unappealing to the eye, downright ugly).
  • On axis the added plate changes the correction towards ‘spherically overcorrected’ when the lens speed is fast, which produces less pleasing background bokeh.
  • In general the sensor cover glass plate shifts the position of the image by about a third of the plate thickness – and that is the point where the dispersion of the plate itself comes into the game, since in the imaging field with oblique rays a longitudinal shift is always connected to a lateral shift. This effect modifies the lateral chromatic correction of the lens.

See also

Durable and fast, up to 1800MB/s
B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 12 hours unless noted. Certain deals may last longer.
$2699 SAVE $300 = 10.0% Canon 11-24mm f/4 EF L USM in Lenses: DSLR
$774 SAVE $222 = 20.0% $100 GIFT CARD Pentax 10x43 Z-Series ZD ED Binocular in All Other Categories
$1497 SAVE $400 = 21.0% $82 FREE ITEMS Pentax K-1 DSLR in Cameras: DSLR

diglloyd Inc. | FTC Disclosure | PRIVACY POLICY | Trademarks | Terms of Use
Contact | About Lloyd Chambers | Consulting | Photo Tours
RSS Feeds | Twitter
Copyright © 2008-2017 diglloyd Inc, all rights reserved.