Focusing Issue with Sigma 100-400

[orchidpoet]

I have some focusing issues when trying to capture birds in flight. It was reasonably easy before, and now I can rarely get a sharp bird even at 2000/sec

But if the birds are not moving, the images are sharp.

I use a Sony mirrorless with a Sigma converter.

Before I send the lens in for repairs, I just want to make sure I did not do some wrong myself.

What are your focus settings?

Thanks!

[Shortsighted]

I presume that you turned off your image stabilization completely, although
both stabilization settings for this lens offer poor stabilization performance
and that is probably one of the reasons that this lens is less expensive. Stabilization
technology is expensive. I've heard of others that have had trouble with this lens
trying to capture a sharp image of a moving target when coupled to a mirrorless
camera but I do not know why this happens so often. Perhaps you could research
it to see if there is an explanation ... ie) "mirrorless camera coupled to Sigma 100-
400 lens". I would do it but the discussion concerning gear is too depressing when
I know I can't afford any of it. So, I'll let you do that.

[orchidpoet]

SS, thanks for your reply.

What are your settings?

Because it worked well before, I wonder if I have messed up with some selections.

[Shortsighted]

What are my settings? That's rich.
My lens doesn't have any settings, except AF = on/off.
Since I do not have IS on my lens I don't need to disengage it when panning for a flying
bird. Panning with image stabilization engaged can cause problems. I have no experience
with mirrorless cameras since I can't afford that either. If everything worked before maybe
you are the problem. You might have to abandon the mobile phone before panning. Just kidding!
Try a controlled experiment repeating the task over and over again and then try again with
a different lens and compare the results. Maybe you are a perfectionist and are expecting too
much. Also, set your minimum focus setting to the greatest distance/ I think your lens has three
settings the closest being 1.6 meters.

[orchidpoet]

You are right, SS, I should test more.

In the meantime, if anyone can share the settings, I'd appreciate very much!

[Shortsighted]

OK, without IS (or VR, OS, etc) I have shot flying birds at anything from 1/4000 sec
to a slow as 1/800 sec, usually wide open at f4, or perhaps f5.6.

With Tree swallows whizzing past my 200mm lens at great speed I am panning as fast
as I can. I'm getting a little dizzy recalling it. That demanded I use a very fast shutter
speed of 1/4000 sec.


For a group of Canada geese I used 1/3200 sec wide open:


For a Hummer I used 1/1600 sec:


Then I discovered most flight shots were at 1/1250 sec:




The slowest speed I ever used was 1/800 sec:

[Paul O'Toole]

Have you tried any flight shots without the Sigma converter?

[Freddie]

Have you tried any flight shots without the Sigma converter?

Now that's an interesting point as I was having difficulty getting consistently focused/sharp images using my new 90D with the 1.4x/100-400 IS mk2.. When I removed the extender I noticed a dramatic improvement

[orchidpoet]

SS, your shots are beautiful!

Sometimes the birds are flying fast, Which autofocus selection should I use? I now use Continous AF (AF-C).

My next question is, which auto focus area should I choose?

When I use manual focus selection, it's not a problem. However, when the birds are flying past, I cannot move my heavy lens (for me it's heavy) fast enough.

Paul and Freddie, yes, I have used the lens on my Canon in the past, it worked well. I haven't tried Canon lately. Maybe I should.

[orchidpoet]

I will try Lock-On AF Expand Flexible Spot.

[Shortsighted]

On my old Canon D650 I am using Al-servo focus (best to following a moving subject)
with center weighted focus and light meter. As far as the TC goes, when I read converter
I imagined an adapter of some kind to couple the Sigma lens to a Sony mirrorless
mutant ninja camera. I would think the focal plane on that Sony is at distance from
the lens coupler that may not suit a third-party super telephoto and therefore required
an adapter to correct the lens proximity. In other words, I wasn't even thinking tele-converter,
which is usually designated as having a magnification factor (1.4TC, 1.7TC, or 2TC) and you
didn't mention that. I would never have tried using a third-party super tele with a third-party 1.4TC and try
to quickly pan a flying subject. I would be very surprised if the Sigma TC produced an
image as clean as the lens itself, which I will admit has been described as very good,
particularly regarding almost no chromatic aberration, something that usually can only
be achieved with multiple coating for each element in the lens at mind-boggling expense.
Why don't you post some of your flight shots so that I can get jealous.

[orchidpoet]

SS, I am just a newbie in bird and wildlife photography. You will never be jealous of my images, lol.

It seems my new setting is working. Thinking about it, it was my old setting. A few weeks ago, I had to re-set my camera to the default, and I could not remember what I did. Now I do.

I went out, but could not find anything flying.

This link would show you my initial shot with the Sigma lens with converter. It was shot at 1/80.

https://fineartamerica.com/featured/red-tailed-hawk-fledgling-crying-charline-xia.html

[orchidpoet]

This is what I shot this afternoon.

Not the best shot, but at least I know it's focusing ok.

https://charline.pixels.com/featured/humble-female-house-sparrow-charline-xia.html

ISO1000, F/7.1,1/1250
Focal length 315

[Shortsighted]

I'm glad you managed to work out the problem. Resetting the camera for non-bird shots and then
forgetting to return it to birding mode happens time and again. Drives me crazy. I've lost many
shots because of a failure to recapitulate to the preferred settings. If I only had a brain. Your
photos seem very crisp for a third party 400mm zoom lens coupled to a 1.4TC. Considering that
you are losing an f-stop with the TC and that this lens is only f6.3 I'm surprised that your AF can
handle it. My old Canon supposedly can only AF reasonable well at f5.6 or faster but I guess the
new mirrorless cameras perform better. I would imagine that you need to boost the ISO to get a
fast enough shutter speed for that level of optical magnification on a lens with mediocre image
stabilization capability. Even wide open at f4 I find it difficult to get a fast enough shutter speed
to compensate for not having image stabilization. I'm always boosting the ISO to levels I would
prefer to avoid, especially when I know I will need to crop due to lack of power. 200mm isn't much
for birding.

[orchidpoet]

SS, I just added the specs:
ISO1000
F/7.1,1/1250
Focal length 315

The image can be sharper if I shot at lower ISO, or if I handled noise reduction better.