Upgrade the memory of your 2020 iMac up to 128GB
Today’s Deal Zone Items... Handpicked deals...
$280 $230
SAVE $50

$100 $100
SAVE $click

$4499 $3499
SAVE $1000

$1398 $898
SAVE $500

$649 $449
SAVE $200

$7595 $5995
SAVE $1600

$799 $499
SAVE $300

$2598 $2398
SAVE $200

$1498 $1398
SAVE $100

$249 $219
SAVE $30

$1699 $1299
SAVE $400

$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

$1636 $1036
SAVE $600

$1699 $1299
SAVE $400

$1199 $1099
SAVE $100

OWC Envoy Express

World’s first Thunderbolt 3 M.2 NVME SSD enclosure.

Super fast, bus-powered, 3.3 oz, DIY easy, rugged and compact!

See also OWC Express 4M2
√ No more slow and noisy hard drives!

Zeiss ZM 18mm f/4 Distagon T*

The Zeiss ZM 18mm f/4 Distagon (about $1340) is a relatively inexpensive, but strong performer in my brief field shooting. Like the Leica 18/3.8 Elmar (not tested), its distortion is of the “wave” type.

Composing really mandates use of the optional 18mm ZI viewfinder (about $419), same need as for any other ultra-wide offering. Which unfortunately raises the price by about a third.

Unfortunately, I did not have the viewfinder while I shot the 18/4 Distagon, so it was a real challenge framing the subject.

View near real-time pricing and availability for Zeiss ZM an Leica M lenses on the Leica M gear page.


I found it easy to focus the ZM 18/4 accurately using the rangefinder. Rangefinder accuracy doesn't change with focal length, so precision should be excellent with a 18mm, and this is what I observed.

Guide to Leica

Image quality

Performance is very crisp and contrasty, with richly saturated color and excellent detail across the frame, even wide open. Stopping down to f/5.6 yields oustanding results, but results are already excellent wide open at f/4.


Setting M9 Lens Detection to “16/18/21 ASPH f/4 @ 18mm 11626” yields less vignetting but not an improvement in color, which is skewed at left and right, though not nearly so much as with the 21/4.5 C-Biogon.

Unfortunately, there is no Lens Detection setting for the 18mm f/3.8 Super-Elmar-M listed in the M9, so it cannot be chose. This is because the Leica 18/3.8 Elmas has always been 6-bit coded, hence no support for any other 18mm lens.

Without lens detection, color images will suffer with the 18/4 Distagon, and thus it can only be recommended for black and white work, unless you’re willing to make a layer mask in Photoshop for post-processing.

Aperture ring

As with the other ZM lenses, the 1/3 stop click stops feel fantastic, and they are easy to see. I love this aspect of the ZM line, and it’s practical too: it allows fine-tuning exposure to 1/3 stop, something that can be of use with digital (expose to the right). They are clear and well marked on the outside barrel of the lens, nicely done, and the slight clicks they make offer excellent auditory and tactile feedback.

New Mac?

Work from home?
Consult with Lloyd before buying!

System configuration for CPU, GPU, memory, SSD, backup, RAID, optimizing performance, workflow.
For YOUR optimal workflow

Avoid costly mistakes in throwing money at the problem for less performance and/or buying the wrong machine for your own needs!

Remote screen sharing available for RAID, software configuration, etc.

More about 2019 Mac Pro vs iMac 5K vs iMac Pro...


The two-step is OK with some practice: focus, then compose with the hot-shoe mounted viewfinder. There is no choice anyway, this is the same with any 18mm lens on the Leica M9.


The ergonomics are excellent, setting aside the need for a separate viewfinder. I liked using the 18/4 Distagon, but it’s larger than the 21/2.8 Biogon, and I preferred the more compact size of both of the 21mm lenses. Still, the 18/4 Distagon shares the same excellent focusing ring and aperture control, and I think I’d be equally at home with it.


Per Zeiss. See the datasheet.

Zeiss ZM 18mm f/4 Distagon
Focal length: 18mm
Aperture scale: f/4 - f/22
Focusing range: 0.5m - infinity
Angular field, diag./horiz./vert 898/87/65 °
Coverage at close range: 56 cm x 84 cm
Image ratio at close range:            1:23
Number of elements/groups: 10 elements in 8 groups
Filter thread: M 58 x 0.75
Weight: 350g
Dimensions (with caps): ø 65 mm, length 71 mm


The distortion of the 18/4 Distagon is the typical wave-type distortion: barrel distortion that reverses to pincushion distortiong near the edges.

Distortion of the Zeiss ZM 18mm f/4 Distagon
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!
OWC Thunderblade Thunderbolt 3 SSD

Blazing fast, up to 16TB.


√ 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!

Deals Updated Daily at B&H Photo

View all handpicked deals...

SanDisk 256GB Extreme PRO UHS-I SDXC Memory Card
$100 $100
SAVE $click

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.