Sigma's Dock.. a doodle doo?

[Rand47]

... or 2) Sigma has just revolutionized lens calibration.

I wouldn't go that far, but I do think it means Sigma is aware that a single micro focus adjustment is sub-optimal and has improved the situation considerably.  When I was doing research on the options available for lens calibration, I did find multiple complaints from users that indicated that making the focus "perfect" at one distance made it worse at others.  This was especially true for those calibrating zoom lenses where both focus distance and focal length compound the difficulties.

Rand

[MarkL]

That's not necessarily the ideal - just the easy, 'Apple-style', all-in-one-package solution.

Look at professional equipment in most fields - most are not all-in-one packages, but endlessly customisable and adjustable, for different operating conditions. This goes for everything from prostheses used in orthopaedic surgery to precision rifle scopes. You don't just take a pre-packaged hip joint and whack it in a person, or a pre-packaged rifle scope and stick it on a gun. You take the parts, then customise, adjust and calibrate it until you get the perfect piece of equipment for the job you're trying to do. I welcome the same approach in a camera system, and like the fact that Sony's A7 series has also, to some degree, made camera systems modular - that is, you take a body from one place, a lens from another and accessories from a third party, to put together an optimal kit for the task, rather than just taking a pre-packaged, all-in-one solution (with all its upsides and downsides) from a single place.

With dslrs we are talking about mid-range mass produced essentially consumer products. Cameras don’t have complicated interfaces with other systems made by other manufacturers, they don’t have calibrations and settings that drift and depend on environmental variables like moisture or human bodies. These cameras just won’t focus properly with other parts designed to work with it from the same manufacturer.

This is like buying a new Ford with an options package but not being able to drive it properly until you align all the wheels and map the ECU yourself because Ford can’t bothered.

At least this will all be over once the slr dies!

[kers]

With dslrs we are talking about mid-range mass produced essentially consumer products. Cameras don’t have complicated interfaces with other systems made by other manufacturers, they don’t have calibrations and settings that drift and depend on environmental variables like moisture or human bodies. These cameras just won’t focus properly with other parts designed to work with it from the same manufacturer.

This is like buying a new Ford with an options package but not being able to drive it properly until you align all the wheels and map the ECU yourself because Ford can’t bothered.

At least this will all be over once the slr dies!

I agree to some extend- i like the dslr for its optical viewfinder- Once that is gone it will never come back. I wish they would make the quality better like the Nikon F3.
I use nikon bodies and focus adjustments are really critical. It takes me half a day to get the focus right for all my lenses. After that i can truly hit focus @F1.4.
The thing i do not like is that in the manuals a chapter is lacking about this focus finetuning problem. As if Nikon is ashamed that they cannot do it right and won't like to admit it.
It took me a year to find out why my autofocus was so off. I thought at the time the AF could not do any better; until i realized it all had to do with finetuning.

[MarkL]

I use nikon bodies and focus adjustments are really critical. It takes me half a day to get the focus right for all my lenses. After that i can truly hit focus @F1.4.

The sigma dock is great but on this point the pain is real. I did a prime and even going in coarse steps of five and then down to one taking off, changing and remounting the lens each time for 4 distances took... a long time. A zoom would be a long affair. In the end worth it (proper focus) but frustrating and irritating it must be done due to cut corners.

[Ellis Vener]

Just finished using the Sigma Dock + Sigma  Optimization Pro  software to tune a Sigma 24-35mm f/2 HSM Art lens. Yes it makes a big difference over using the in camera Canon AF micro-adjust tool.

External Hardware used (besides the Sigma Dock)
LensAlign Mk II (Gen 4) target in a RRS FAS clamp mounted on a RRS CB-18+CB-10 rail combination. the 28" rail combination was mounted on two tripods ( one fore and one  aft), sandbagged to ensure a fixed alignment.
(yes I am being very obsessive about this but since I already had the hardware, why not use it?)
- Lightsource;  Monolight with hard reflector (Specifically a paul C. Buff, Inc Einstein E640 with the new 18" Omni Reflector andd its heaviest diffuser sock, even so the Einstein was near minimum power)

Workflow:
1) Started with the LA target at the closest distance recommended in the SOP app,  the closest position,  the LensAlign target was centered and squared to the sensor in the usual way, and the lens set  at its defaults zeroed for each focal length and distance, and with the camera's AF-MA zeroed for both shortest and longest focal lengths.

2) Shot frames at the four recommended focal lengths: 24, 28, 30, and 35mm.  Defocused the lens slightly between frames.

3) Examined the frames ((camera-shot JPEGS (fine/large)  at 100% and 200% Lightroom CC2015  using the slanted rail of the LensAlign Target as a guide to which direction and by how much to adjust lens for each focal length. Surprisingly the numbers on the scale on the lensAlign ruler tended to be very close to how much adjustment was need ed for each frame.

4) Dialed in the corrections for each focal length as needed and retested.

5) As needed , ran the test a third time.

6) Moved target to the next farthest distance and repeated steps 2-5.

7) Moved target to the third distance and repeated steps 2-5

This portion of the test took about 2 hours what with going back and forth to the camera with SD card and lens and the usual mundane  interruptions.

For the infinity test  I took the camera outside  and with the camera on a tripod, used the corner of a neighbors brick house as target,


Conclusion: yes  the Sigma Dock and software  makes a difference, especially if you shoot wide open (f/2 in this case which even with the lens at 24 doesn't have a lot of depth of field. I had previously spent the entire afternoon yesterday using the camera's AF-MA and the same target and FocasTune software and my results not as good and I could only "optimize" at the longest and shortest focal lengths and with the target at only one distance (25x focal length) for those two focal length settings.

[MarkL]

Surprisingly the numbers on the scale on the lensAlign ruler tended to be very close to how much adjustment was need ed for each frame.

I bet this reduced the time by a lot, I did it is steps of five and then ones for the range that would have the right setting in it. I wish it didn't need a dock and I could just plug in a micro-USB lead; it is the mounting, waiting for the lens to register and then click through the software that makes this process to tedious and time consuming.

Luckily it only needs to be done once!

[Ellis Vener]

"I wish it didn't need a dock and I could just plug in a micro-USB lead; it is the mounting, waiting for the lens to register and then click through the software that makes this process to tedious and time consuming. "

I totally agree. Maybe it has something to do with being connected to the camera at the same time. But you could turn the camera off between changing settings with the Sigma software. I am just speculation here but it might also have something to do with  the problem of keeping the port closed and sealed against the elements.

[Torbjörn Tapani]

A Micro usb port could fit in the mount flange perhaps?

[Hulyss]

I realize how much film is easier to shoot, sometimes. No real focus problem with sub par 35mm fslr. No need of super-stellar lenses too. I'm amazed how, for example, the Nikon f1.8 line max out films. The digital world is more and more expensive...

[Ellis Vener]

I realize how much film is easier to shoot, sometimes. No real focus problem with sub par 35mm fslr. No need of super-stellar lenses too. I'm amazed how, for example, the Nikon f1.8 line max out films. The digital world is more and more expensive...

Back in the film days, many top pros bought their gear through shops that careered to the professional crowd and try out several iterations of a single lens to find the best one. I learned that trick from Al Satterwhite, and then often had there lenses and cameras calibrated, ground glasses shimmed into the right position, and otherwise adjusted by genius mechanics like Marty Forscher in New York City. Life Magazine and National Geographic had their own techs who calibrated and repaired cameras and lenses as welll as building special cameras and lenses.

That we as individuals now have the power to tune our SLR cameras to the specific individual lenses we use, is in my opinion a boon, but like all powerful craft , is a craft that needs to be respected and learned.

Just be happy (or sad, depending on your OCD level) we can't also collimate our own lenses!