Yes. For the infinity shot, sHoot something far away that has good contrast. Use live view 10x for your first shot. Shoot a series of the pictures using phase detect af and varying your microadjust numbers until you find one that is as sharp as your live view shot.
myron lee wrote:
Yes. For the infinity shot, sHoot something far away that has good contrast. Use live view 10x for your first shot. Shoot a series of the pictures using phase detect af and varying your microadjust numbers until you find one that is as sharp as your live view shot.
I guess I could also use the DotTune or TurboCal methods with a high-contrast target that isn't necessarily a flat focus chart?
Okay, I just finished calibrating—at least the first part. I ran out of time and didn't have time to confirm the values are correct after entering them into the lens. I'm suspicious that they will be, though, because they're so strange:
12": 5
16": -4
26": -2
Inf: -7
There's a 9 point MFA difference between 12-16"?
I tried this in outdoor light and then using two indoor lights. Values were different each time. I calibrated at 69" too, which is 50x focal length, and got a value of +1. It's all over the map. Sigh.
I definitely think user error is a possibility here, but I'm not sure how to remedy it.
Questions:
— What's the most accurate way of measuring from the focal plane? I want to be sure the camera is at the right distances.
— Is there any way of calibrating the infinity value automatically? I've never trusted my eyes for gauging focus using the rear LCD.
It's me, but I get better results using a reference photo using live view focus 10x . I compare my phase detect AF to this live view shot to see if both are equivalent. With the 5Diii, the LCD is good enough to compare at 12x. I think that is like 120% enlargement. The big reason I used live view focus as a reference shoot is because I can see if the lens is defective or not. A slight defect, and at least 4 of my lens were, and I can never get consistent AF with these lens. My rule is that my copy has to be consistent with the performance of pro reviews posted on the net. Second is that all sides are equally sharp. If one side is blurrier, I send it in for service.
There are reports that some copies of the Sigma35 has a different MA with artificial lights. I think it was +8 difference for many. That was the first thing I tested for, because my sig50 once did that. I sent the 50 to Sigma NY and they fixed it.
I used a yard stick to measure my distances from a tilted chart as well as a flat surface. The distance is to the sensor which is close to the back of the camera body.
badlydrawnboy wrote:
There's a 9 point MFA difference between 12-16"?
So is your real world shots blurry at 12 or 16 inches? Trust your eyes and use a magnify glass / or close up glasses if you have to. Dot tune sucked for me at MFD ranges.
Use +1 for your infinity set point to start with if you are certain it's a satisfactory value at 69 inches.
myron lee wrote:
It's me, but I get better results using a reference photo using live view focus 10x . I compare my phase detect AF to this live view shot to see if both are equivalent. With the 5Diii, the LCD is good enough to compare at 12x. I think that is like 120% enlargement. The big reason I used live view focus as a reference shoot is because I can see if the lens is defective or not. A slight defect, and at least 4 of my lens were, and I can never get consistent AF with these lens. My rule is that my copy has to be consistent with the performance of pro reviews posted on the net. Second is that all sides are equally sharp. If one side is blurrier, I send it in for service.
There are reports that some copies of the Sigma35 has a different MA with artificial lights. I think it was +8 difference for many. That was the first thing I tested for, because my sig50 once did that. I sent the 50 to Sigma NY and they fixed it.
I used a yard stick to measure my distances from a tilted chart as well as a flat surface. The distance is to the sensor which is close to the back of the camera body.
Thanks. If I were to send this lens into Sigma along with my 5DIII, I wonder if they use a dock to calibrate it? Or have they always used something like that, and they're just now releasing it to the public?
I just got the dock, and today I employed it. I already had the lens MA set to 3 on my 5D III, and I decided to leave it there for testing the four distances with the dock. It was perfect with no adjustment at 12" and 16", but I needed to set -2 at 26". Infinity just isn't sharp wide open, period; has anyone else experienced that?
I did this again in an indoor space with natural light, stable tripod, and precise measurements. I did both the semi-automatic calibration method in Focal, and Turbocal, which I believe emulates the DotTune method. Here are the results:
Semi-automatic method
12" +14
16" +13 / also failed result, low confidence
26" +15
Infinity: not calculated yet
TurboCal
12" +18
16" +18 (did not hear any beeps until +16)
26" +19
Infinity: not calculated yet
Note that Focal said it couldn't find the target at 12" (possibly too close; have you experienced this?). I haven't calculated infinity yet because the light is mottled and inconsistent in my backyard, and there's no indoor space where I can get 100 feet away. The other issue is that I got an "unexpected results, Focal is adding more test points" a couple of times and had to stop the test due to Focal telling me it had low confidence in the results. At 12" I got a "failed to focus" error I've never seen. I know it wasn't too close to the target because Turbocal worked from the same position, and I could acquire focus with both LiveView and phase detect myself. I'm not sure if that was because of a subtle change in outdoor light coming through the window, or what.
Also frustrating that the TurboCal and automatic methods are significantly different, and this entire set of results is very different than the ones I did yesterday with artificial light.
I really, really want this lens to work out—I'm so impressed with the optics. But this is my third copy, and the whole calibration process is so time consuming (assuming it even works with this lens, which is not certain at all given the failed test results I had). I didn't have the dock for the first two copies, but I'm not sure having it this time around is going to make a difference.
My 50L, Sigma 85, Canon 135 and 24-70 II are all calibrated within a +/- 3 range of zero. But every Sigma 35 I've tried so far has been above +15, and even then it would be accurate at some distances and not others. What do you think? Should I send it in to Sigma? I don't think a 4th copy makes much sense. Or maybe just throw in the towel and pick up a used 35L? I considered the 35/2 IS, but I already have the 24-70 II and the reason for a 35 prime is for lower light indoor use.
p.4 #10 · Sigma USB Dock calibration data for 35mm
Without even taking into account the many other members' good results, just based on my copy alone I'd recommend letting Sigma have a go at it. There doesn't appear to be anything inherent with the lens that would prevent accurate AF at varying distances, so Sigma should be able to figure it out and make it right... at least I'd hope so; I've never dealt with Sigma customer support.
p.4 #11 · Sigma USB Dock calibration data for 35mm
I dunno but it looks like some folks try to bring MFA to a different level here . Keep one thing in mind, we are not talking about a high precision laboratory equipment/device here that requires 100% consistencies that can be repeated over and over again. It is only a camera body and a lens to take pictures, by all means. But whatever floats your boat. I remembered in the early days of the MFA, I used to leave the MFA on my lenses unadjusted when the value was less than 2 or even 3 in either direction. I didn't have any issues back then .
Fortunately, my Sigma 35mm performs as specified without any issues, even at wide open at various distances.
p.4 #12 · Sigma USB Dock calibration data for 35mm
badlydrawnboy wrote:
I don't think a 4th copy makes much sense.
I don't think a third copy made sense! I gave up after one. Debated the 35mm f/2 IS as well, but I'm waiting on a price drop.
I picked up the new 28mm f/2.8 IS while it was at $399 shipped, and it's DAMN IMPRESSIVE. I literally can't get it to miss with the AF. Using a 1D4 and a 5D3, and it's mindblowing how accurate this thing is. Low light, good light, indoors, outdoors... It just works. This is how lenses are supposed to perform.
p.4 #13 · Sigma USB Dock calibration data for 35mm
austin.grant wrote:
I don't think a third copy made sense! I gave up after one. Debated the 35mm f/2 IS as well, but I'm waiting on a price drop.
I picked up the new 28mm f/2.8 IS while it was at $399 shipped, and it's DAMN IMPRESSIVE. I literally can't get it to miss with the AF. Using a 1D4 and a 5D3, and it's mindblowing how accurate this thing is. Low light, good light, indoors, outdoors... It just works. This is how lenses are supposed to perform.
If you don't mind a wider lens with less good optics
p.4 #14 · Sigma USB Dock calibration data for 35mm
AGeoJO wrote:
I dunno but it looks like some folks try to bring MFA to a different level here . Keep one thing in mind, we are not talking about a high precision laboratory equipment/device here that requires 100% consistencies that can be repeated over and over again. It is only a camera body and a lens to take pictures, by all means. But whatever floats your boat. I remembered in the early days of the MFA, I used to leave the MFA on my lenses unadjusted when the value was less than 2 or even 3 in either direction. I didn't have any issues back then .
Fortunately, my Sigma 35mm performs as specified without any issues, even at wide open at various distances....Show more →
p.4 #15 · Sigma USB Dock calibration data for 35mm
Sven Jeppesen wrote:
+1
yes some people are over-thinking it
There is a purpose to ultra sharp lens. For me, I am a lazy photographer especially when it comes to street photography. A lot of times I need to crop plenty to get the composition right. So a high resolving lens with big megapixels comes in handy for me. And the USB port pushes the sharpness further creating more flexiblity in cropping options. The S35 has great corner sharpness even at f1.4. More flexibility for me. So if you have a purpose, it is not over-thinking. It is more like sharpening the knife and cutting the fat away. In fact its more like under-thinking when I snap the shot. And I leave it to PP to get it right. There is nothing wrong with that, its just utilizing the new tools available to us.
p.4 #16 · Sigma USB Dock calibration data for 35mm
Sven Jeppesen wrote:
If you don't mind a wider lens with less good optics
It was more of an example of how I expect my lenses to perform, but sure, point taken. I agree that people are taking the MFA calibrating to the extreme, but unfortunately, for a large number of these Sigma 35mm lenses that seems to be required. Mine had completely different MFA values for several distances that were all in the last calibration group, and therefore couldn't all be accounted for.
My point wasn't to bash the Sigma or to show that a 28mm f/2.8 was a good alternative...it's not. It's very different. Well, now that I think about it, yes, it is a good alternative. I'd rather have a focused shot at 28mm and f/2.8 than a dozen out of focus shots from "the best 35mm optics on the planet."
p.4 #17 · Sigma USB Dock calibration data for 35mm
Believe me, the last thing I want to be doing is spending my time MFA calibrating a lens. I don't enjoy it and I am frankly too busy right now to fool around with that kind of thing. That's why it's so frustrating.
When I get a new lens, I don't MFA it right away. I just take pictures. If I notice the focus is off, then I MFA. With the 24-70 II, 50L, 135L and Sigma 85, I did the MFA at 50x focal length with TurboCal (took 15 minutes) and each of those lenses was spot on afterward.
With my first two copies of the S35, I did the same process, and it would focus well at 50x focal length, but then front-focus horribly at 10x focal length. This is not my imagination. It doesn't happen with other lenses I own, including the Sigma 85.
As I just want the lens to focus properly at all focal distances. If that's "over-thinking it", then I'm guilty as charged. But to me, that's just a basic expectation I think everyone should have of a lens.
p.4 #18 · Sigma USB Dock calibration data for 35mm
Here's a clear example of what I'm talking about.
After doing the MFA as I described above, I dialed in +18 in camera because that was the value (or within 1 of the value) for 12", 16" and 26". (It was also the value for 50x focal length.) I then took this picture about 2 feet away from the subject:
Obvious back-focus at this distance with this MFA value. I have a number of other similar examples.
This is of course what the dock is supposed to be for, but FoCal was giving me errors when I tried to calibrate it at longer distances—perhaps because of some issue with the lens. I don't know.
I think I will send this in to Sigma. I'm not quite ready to give up, and as Ernie said they should be able to either make it work well or replace it. I guess my fear is getting stuck with a lemon if they don't. Does anyone have experience with Sigma customer service?
p.4 #19 · Sigma USB Dock calibration data for 35mm
myron lee wrote:
There is a purpose to ultra sharp lens. For me, I am a lazy photographer especially when it comes to street photography. A lot of times I need to crop plenty to get the composition right. So a high resolving lens with big megapixels comes in handy for me. And the USB port pushes the sharpness further creating more flexiblity in cropping options. The S35 has great corner sharpness even at f1.4. More flexibility for me. So if you have a purpose, it is not over-thinking. It is more like sharpening the knife and cutting the fat away. In fact its more like under-thinking when I snap the shot. And I leave it to PP to get it right. There is nothing wrong with that, its just utilizing the new tools available to us. ...Show more →
No, there is nothing wrong with doing that at all and as I mentioned in my post, whatever floats your boat. However, to me personally, spending hours and hours adjusting down to an (almost, or maybe already) science level, taking test shots after test shots, seems to be excessive. Somehow, that seems like taking away the fun part of photography, the art of capturing images. YMMV, I guess.
p.4 #20 · Sigma USB Dock calibration data for 35mm
badlydrawnboy wrote:
Here's a clear example of what I'm talking about.
After doing the MFA as I described above, I dialed in +18 in camera because that was the value (or within 1 of the value) for 12", 16" and 26". (It was also the value for 50x focal length.) I then took this picture about 2 feet away from the subject:
Obvious back-focus at this distance with this MFA value. I have a number of other similar examples.
This is of course what the dock is supposed to be for, but FoCal was giving me errors when I tried to calibrate it at longer distances—perhaps because of some issue with the lens. I don't know.
I think I will send this in to Sigma. I'm not quite ready to give up, and as Ernie said they should be able to either make it work well or replace it. I guess my fear is getting stuck with a lemon if they don't. Does anyone have experience with Sigma customer service?
. Keep one thing in mind, we are not talking about a high precision laboratory equipment/device here that requires 100% consistencies that can be repeated over and over again. It is only a camera body and a lens to take pictures, by all means. But whatever floats your boat. I remembered in the early days of the MFA, I used to leave the MFA on my lenses unadjusted when the value was less than 2 or even 3 in either direction. I didn't have any issues back then 