Latest or all posts or last 15, 30, 90 or 180 days.
Memory Upgrades for 2019 Mac Pro - Save Up to 65% vs Factory Costs
877-865-7002
Today’s Deal Zone Items... Handpicked deals...
$4499 $3499
SAVE $1000

$1398 $898
SAVE $500

$649 $449
SAVE $200

$7595 $5995
SAVE $1600

$799 $499
SAVE $300

$2598 $2398
SAVE $200

$700 $500
SAVE $200

$1498 $1398
SAVE $100

$249 $219
SAVE $30

$1699 $1349
SAVE $350

$21999 $19999
SAVE $2000

$8399 $7599
SAVE $800

$1149 $799
SAVE $350

$260 $180
SAVE $80

$4998 $3998
SAVE $1000

$569 $519
SAVE $50

$899 $799
SAVE $100

$2347 $1997
SAVE $350

$883 $633
SAVE $250

$1299 $949
SAVE $350

$1699 $1349
SAVE $350

$1199 $1099
SAVE $100

OWC Envoy Pro EX SSD
Blazingly fast Thunderbolt 3 SSD!

Up to 4TB capacity, USB-C compatible.

USB-C model also available


Great for travel or for desktop!

Sigma 105mm f/1.4 DG HSM Art Assessed for Focus Shift: Wooden Surface of Picnic Table

Get Sigma 105mm f/1.4 DG HSM Art for Canon, Nikon, Sony mirrorless at B&H Photo.

This page assesses the Sigma 105mm f/1.4 DG HSM Art for focus shift at a distance of approximately 1.5 meters.

One might think that a “small” amount of focus shift is acceptable. But it is not—I think I at first unfairly blamed the Nikon D850 for focusing errors in the f/4 and f/5.6 images. It might well be a factor, but the dominant error seems to be the zone of sharp focus being too deep, e.g., centered inside the eyeball instead of centered on the iris of the eye. This series explores that theory, with definitive results/

Sigma 105mm f/1.4 DG HSM Art: Assessing Focus Shift @ ~1.5m: Picnic Table Wooden Surface

The interesting 'twist' here is that Sony mirrorless cameras focus at the shooting aperture*, thus eliminating focus shift as a consideration. That, combined with the near-perfect hit rate of Sony Eye AF (see Autofocus Configuration for Sony A7R II and Siblings: Buttons and Eye AF) should prove interesting when the Sony-mount version arrives.

* This might have changed with a firmware update, and it might depend on variables such as the scene brightness—some research needed to see the current behavior in dim or bright light, and it might also depend on lens brand (Sony, Zeiss, Sigma, etc).

f4 @ 1/125 sec, ISO 64; 2018-07-04 18:16:24
NIKON D850 + Sigma 105mm f/1.4 DG HSM Art

[low-res image for bot]
OWC Thunderblade Thunderbolt 3 SSD

Blazing fast, up to 16TB.

YEE HAH!



√ No more slow and noisy hard drives!
OWC Accelsior 4M2 PCIe SSD
6000 MB/sec!
Mac or PC.


Ideal for Lightroom, Photoshop, video.
Capacity up to 16TB!

Save the tax, we pay you back, instantly!
View all handpicked deals...

Sony Alpha a7 II Mirrorless Digital Camera (Body Only)
$1398 $898
SAVE $500

diglloyd Inc. | FTC Disclosure | PRIVACY POLICY | Trademarks | Terms of Use
Contact | About Lloyd Chambers | Consulting | Photo Tours
RSS Feeds | Twitter
Copyright © 2020 diglloyd Inc, all rights reserved.