arbitrage
Offline
• • • • • • •
Upload & Sell: On
|
 p.1 #7 · Can someone school me on the Sigma 150-600 C adjustments | |
Brian at TDP has the most in depth info on the options for the dock at this link http://www.the-digital-picture.com/Reviews/Sigma-150-600mm-f-5-6.3-DG-OS-HSM-Contemporary-Lens.aspx
Here is the relevant paragraph....
Focusing
Driven by Sigma's HSM (Hypersonic Motor), the Sigma 150-600mm OS Sports Lens is fast-focusing out of the box. I say "out of the box" because the focus speed performance attribute can be configured using the Sigma Dock. Basically, the slower (Sigma references "smoother" instead) the lens focuses, the greater the chance that the lens focuses accurately.
The default "Standard" option is designed to provide a balance of speed and accuracy. By configuring one of this lens' two custom modes (switch selectable), faster (Motor's drive speed-priority) and slower (Focus accuracy-priority) focus drive speeds can be selected. You may find the slower speed to be the better low light option while the faster speed may prove great for your high contrast in-action subjects under bright light.
Place clearly delineated subject with good contrast on a focus point and this lens locks focus very quickly in "Standard" mode and even faster in "Motor's drive speed-priority". The differences between the three focus speed modes is noticeable, but I used the Standard mode for most of my testing based on the expectation that Sigma made this the default mode with good reason.
As great as fast-focusing lenses are to have, focus accuracy is always more important. In the field AF accuracy on both the 5D Mark III and 1D X I was using the lens on has been reasonable and that includes AI Servo performance at several sporting events I captured with this lens. Reasonable, but not perfect was AF Consistency. In four separate controlled AF test sessions, I found some focus accuracy inconsistencies especially noticeable at the wide end of the focal length range.
So, I theorized. The 150-600mm Sports lens showed very good focus accuracy. The same company introduced both lenses at nearly the same time, so the same AF technology and algorithms were available for each. The Contemporary's AF speed seems slightly faster than the Sports model and Sigma indicates that faster AF speed reduces focus accuracy. Thus, I theorized that changing the Contemporary's AF speed to the slowest option might bring my accuracy results from this lens up to what I experienced with the Sports version.
I configured Custom Mode 2 for "Focus accuracy-priority" and retested AF accuracy. Unfortunately, this test proved my theory to be incorrect, showing the worst 150mm AF accuracy of the four tests. Here are 100% crops taken from the center of the last six 150mm test images.
The in-focus hit rate shown here was consistent throughout this test. Often (but not always), 600mm images will have shallower depth of field, requiring better AF accuracy. While some focus accuracy inconsistency shows in the 600mm tests, the inconsistency is less significant than at 150mm. A lens that consistently focuses in front of or behind the subject can be calibrated, using the Sigma Dock, Sigma Service or a camera with AFMA capabilities, but an inconsistently-focusing lens is a bigger problem. If you encounter this issue, the best solution may be to take extra insurance shots.
A lens with the max apertures this one has does not require as much focusing precision as a 400mm f/2.8 lens for example, and overall, this lens' in-focus hit rate was reasonable. Again, AI Servo results were similar with a majority of images being properly focused.
By reducing the focus distance range the lens has to hunt through to find the correct focus distance, this lens can potentially lock focus faster. The focus limiter switch is designed for this purpose. Select between 32.8'(10m) - 8, 9.2'- 32.8'(2.8m - 10m) and the full range of focus distances. Don't like any of those options? The dock can be used to create your own focus limit ranges, instantly selectable using the Custom Mode switch on the lens.
Focus calibration issues can cause miss-focusing, which can strongly impact image quality. I did not have focus calibration issues with this lens, but if encountered with your lens and camera combo, the dock can be used to correct this problem. With dock compatibility, consistent front or back focus issues can be corrected in the lens at 4 focus distances for 4 focal lengths (150mm, 250mm, 400mm, 600mm).
The Sigma 150-600mm Contemporary Lens focuses quietly (unlikely to scare off your wildlife) with the typical shuffling of lens groups being just-audible in a very quiet environment. This lens focuses internally and FTM (Full Time Manual) focusing is available. The front element does not rotate with focusing.
Image Stabilization
Optical stabilization can greatly increase the versatility of most lenses, and when the focal length increases to 600mm, especially on an APS-C body, OS can save the day by virtue of the stabilized viewfinder alone. Framing a subject properly at 600mm handheld requires steady arms, but OS reduces the steadiness requirement to include a much greater segment of the photographer population. Sigma has not published the optical stabilization system rating for this lens, but I would be surprised to learn of a less-than-four-stop rating being introduced today.
With good form and stable footing, I could get mostly-sharp handheld results down to 1/15 second at 150mm (using a full frame DSLR) for about 3 1/3 stops of assistance over handholding a 150mm focal length in general. The keeper rate quickly dropped at longer exposure durations and beyond 1/10 second exposures, a very low percentage of images were sharp. One image in 16 was sharp at 1/5 second.
Longer focal lengths with their greater magnification require faster shutter speeds to deliver sharp handheld results than their wider angle counterparts do. At 600mm, the 150-600 Contemporary gives me mostly sharp handheld results down to 1/50 second for about 3 2/3 stops of assistance. The keeper rate was about 75% at 1/40 with sharp images captured sporadically at longer exposure times.
As is common for stabilized telephoto lenses, the Sigma 150-600 features mode 1 (normal) and mode 2 (panning) options. Using the Sigma Dock, this lens' OS can be further configured to one of three settings described by Sigma as:
Dynamic View Mode – This mode offers a recognizable OS effect to the image in the viewfinder. This helps to ensure the composition of images quickly.
Standard – This is the default setting. The OS effect is well-balanced and suitable for various scenes.
Moderate View Mode – This mode offers an excellent compensation of camera shake, and achieves very smooth transition of the image in the viewfinder. The composition of the image remains natural even when the angle of view keeps changing.
The lens comes with "Standard" selected by default. I primarily used Standard mode for my testing (and off while shooting sports), but I prefer Dynamic View Mode for subjects that are not moving quickly.
Some clicks are heard at OS startup and shutdown, but the operational hum is quiet. There is sometimes a small amount of jumping seen at OS startup and shutdown and subject framing drifts a small amount during OS operation (turn off OS when using a tripod). The end results from this lens' stabilizer are good – OS is an important feature for this handholdable long lens.
|
What is sacrificed if I set it that way