• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Micro Four-Thirds (1 Viewer)

Did some focus speed comparisons today. I set up the camera so I could go back and forth from two targets, one 10 and the other about 40 meters away. The positions were blocked so I did not have to look through the view finder, just rock the camera up and down after each shot. I also wanted to see how much juice the Sigma consumes in focusing, so IS was off and no pictures were displayed, only the info panel on the screen. Silent shutter. Focus priority was off, so it would only fire if the shot was in focus.
I shot first with the Sigma and shot until the first green bar on the battery indicator went out, still two showing. Original Oly battery, about three years old.
I got 1018 shots (!) , with the average time between shots 3 seconds. I didn't run the Canon as long, only about 380 shots, but the battery was still showing full. Average time between shots was 3.9 seconds. Neither lens had the focus limiter on. The Canon is faster with it on as it can't get lost looking in the foreground. The Sigma is the same with it on or off. Very seldom gets lost.

Moon tests tonight, though the air does not look all that good. Did some last night, also not really clear, the scope against the Sigma, both with 1.4x TCs, and the Sigma was just slightly less sharp stopped down a stop, but produced more pleasing images, better contrast.
 
Dan,

I just visited the metabones site and looked at the compatibility chart.
http://www.metabones.com/products/details/MB_EF-m43-BT2

It states that the Canon EF 400mm f/5.6L USM is accurate only on newer cameras such as Panasonic G7, GX8 and GX80/85... (which may explain why I perceive that I get a spread of in/out of focus, at least with my copy of the EM-1?)

The Sigma 150-600 is not listed there, yet.

/Tord
 
Tord said:
Dan,

I just visited the metabones site and looked at the compatibility chart.
http://www.metabones.com/products/details/MB_EF-m43-BT2

It states that the Canon EF 400mm f/5.6L USM is accurate only on newer cameras such as Panasonic G7, GX8 and GX80/85... (which may explain why I perceive that I get a spread of in/out of focus, at least with my copy of the EM-1?)

The Sigma 150-600 is not listed there, yet.

/Tord
Click to expand...

That was definitely the case with my 400mm. I had to get rid of it. One day, I may get a Sigma to replace the scope that I don't use anymore.
 
It seems we have a mixed bag of experiences using the EM-1 + Canon 400/5.6 + metabones setup.

I am on one hand very pleased with the weight, form factor, portability, sharpness, lack of CA, contrast however the ratio of shots in-focus requires a burst to be taken to be on the safe side. I'd say the probability for a frame with correct focus something like from around 50% when shooting a single frame to virtually 100% when shooting 5 frames. Sometimes I get 2 to 3 sharp frames out of 5. I am sure that the focus is changed in between frames, minor adjustments but still enough to turn what would have been a great picture into a mediocre one.

I tested my lens on another EM-1 copy and got the same behavior so the issue is on the lens side of the metabones. Maybe the FW keeps on changing the focus after focus has been acquired by the camera? Maybe there is a more or less pronounced "delay/feedback loop" that causes this, how much is depending on the lens copy?

With above behavior I am inclined to agree with Metabones that focus is not accurate. I would call it "unreliable". Metabones must have received reports from the community about this, otherwise they would have listed it as supported/accurate AF.

Would be interesting to test with other lenses listed as "supported" as well as other lens models/copies.

Luckily, frames are for free. It just takes some more time to delete the bad ones.
 
Also. still trying to find out from Metabones whether an external USB power bank would provide the lenses with more juice and make them focus faster. Still no answer, though....
 
B :)
I like the way he kept his eye steady while the branches were moving. 40 meters away and he had me nailed!
The night before the air was not bad so I went after the moon again. Pretty clear who the winner is here!
31359055482_615b2a05a3_h.jpg
31390194211_aeef965ff7_h.jpg
 
Last edited:
Tord,
I have done some burst tests to try and replicate what you are saying about the focus with the 400. I tested both it and the Sigma. In bursts with silent shutter there is zero difference between the frames (12), and the focus isn't even one millimeter off. BUT.... with the mechanical shutter, even set to antishock=0, there is a noticeable difference between the first frame of the burst and the following frames. The focus is the same, but the slight vibration within the camera is enough to knock the sharpness down a notch. This is a common phenomenon that affects all cameras with mechanical shutters. The degradation is less with the Sigma (3.2kg) than the Canon (1.3kg) which also stands to reason.
I am going to make a better test chart, but this is good enough to see what is going on.
PC091558.jpg PC091559.jpg PC091566.jpg PC091567.jpg

So I am wondering if what you are really seeing is "shutter shock" and not focus shifting. The Metabones has no "mind of its own". It can only send instructions from the camera to the lens. It does not generate instructions. And in S-AF at least, the focus freezes with the first shot.
I'll try the same test later with C-AF, though I find it still totally useless in anything moving faster than a snail on Valium.
 
Dan,

Thanks for spending time on this. What I am experiencing is not shutter shock (even though it can sometimes be seen when shooting at critical speeds, but then the whole image is blurred). Focus varies between frames. The ones with best focus are usually the later one(s) in the series, but not always. I remember Jules writing in a post about the OOF issues increasing with distance and am inclined to agree with that.

I should probably conduct a more serious test to demonstrate and convince you.

I am also thinking of giving the good old trusted E-M5 a workout to see if same symptoms with OOF. I have only taken a few test shots so far and the results looked OK.

Stay tuned...
 
You don't have to convince me of anything. I am just trying to understand what is going on. ;)
I did some testing with C-AF (same stationary target), first with V2.1 and then with v2.5. 2.1 would not even acquire focus! 2.5 did, though slowly. With AS=0 burst the frame rate dropped to about 3-4fps. It is set at 6.5. The slight blurring is there, but not as pronounced as the camera has more time to settle. In silent mode everything stayed sharp. The acquired focus was spot on all the time.
The bluring is on a pixel level and cannot be seen as typical shutter shock, just a general softening of the picture.
You must test this in a controlled way. Hand held shots of birds allow SO many other factors into the equation. Eliminate the variables and then you can narrow the problem down.
The shutter of the E-M5 is less prone to SS than the E-M1. You can just tell by the sound. Remember the time we were shooting the Avocets in Scanör? You were standing just two meters away and I didn't think you were shooting at all.
 
Tested the Sigma at 400mm. It front focuses a tad so it does in fact need fine tuning. The USB dock is on the way to do just that. Very refined fine tuning system. Still...
C-AF AS=0- slow frame rate, not much difference between the shots
C-AF silent- slow but everything sharp
S-AF AS=0- normal frame rate, but bigger difference between the first and the following shots
S-AF silent- normal frame rate, everything sharp
 
My 400mm had focusing accuracy problems with BOTH electronic and mechanical shutters. Using S-AF, not C-AF which was useless.

Let us not forget that the Canon 400mm is quite an old lens, dating back May 1993...
 
Hmmmmm.... :C

Thanks! I will definitely look into that. But I can still fine tune without updating the firmware. Some have said there SEEMS to be some speed improvement after updating, others see no change. Rather not risk it.
The Sigma TC is nowhere near as good as the Canon from what I have seen.

Later...

It could simply be a body specific AF thing. Logically, a Canon mount Sigma will be used on a Canon body, (but who says I am logical?). But only a few of them even auto-focus to f/8, and an f/6.3 lens + 1.4xTC= f/9. The 2x TCs are not supposed to AF at all, but both work flawlessly on the E-M1, which even with the 2x TX attached, still has 37 active AF points! And they work.... and they are accurate....Take that Canikon!

At any rate, we are talking about MICRO adjustments, like maybe 1-2mm at 5 meters. The focus peaking is great because it tells you immediately where the focus is. No need even to take pictures... :)
 
Last edited:
If I am really careful about centering the AF field right in the center of the target, it is spot on 10 out of 10 times. On my resolution test chart also. So maybe the "back focusing" was carelessness on my part; having the AF point maybe too high...? It stands to reason that there will be no front or back focusing as the AF points are on the sensor. Probably could have saved the money for the dock.:-C
 
Daniel - I'm looking forward to see you with the e-m1 mk2 and testing with what you got now :)

(sell what you have to finance it - ;-) )
 
My telescope expert friend lent me his new Canon 100-400 II to test, so I have spent the afternoon doing three way comparisons, resolution and AF. The IQ from the 100-400 is slightly better than the other two, but in reality, all three are about the same in terms of sharpness. The 400/5.6 has a little less contrast due to higher CA, but it is not so bad. The shots from the 100-400 though, have more punch and overall clarity than the other two. BUT... it is PAINFULLY slow to AF on the E-M1. AF is best by a good bit with the Sigma, but the 400 is not that far behind.
So, Carlos, in a way you are right. At the moment it looks like the best thing to do would be to get an E-M1 II and see how it goes. My guess is there would be more to gain there than from the Sigma. I can always get my friend's 100-400 to re-test if I do get a Mark II. If it really is superior focusing the Canon 100-400 that would be a serious consideration.
The build of the Sigma is far above the Canons. Really solid! Just not that much of an advantage for me.... we'll see. I am in no rush.
 
Warning! This thread is more than 7 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Similar threads

S
Using iPad as monitor for DSLR Digiscoping
Replies
0
Views
546
SwannyVancouver
S
MelospizaMelodiaFan
Upgrading from Bridge Camera to M43
2
Replies
26
Views
2K
Missy_MT_AK
M
O
Canon EOS 80D always slightly "fuzzy"
Replies
14
Views
2K
nikitasius
N
C
AX Visio: is it really as bad as some reviewers claim??
2 3 4
Replies
68
Views
7K
Canip
C
W
Considering a Partial Camera Upgrade - D500 w/ 200-500mm lens
2
Replies
34
Views
4K
BriLee
B

Users who are viewing this thread

Total: 2 (members: 0, guests: 2)
Back
Top