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Fuji X-T2 +100-400 + 1.4

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twan

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I'm using this combo but i have the feeling that auto focus is a bit inconsistente.

I took pictures at 400 mm + 1.4 that were perfectly sharp and others at the same moment where the focus was just a bit off. Does this sound familiar? I cannot explain this.

I had the same issue with my X-T1. It makes me unsure about the use of the 1.4
 
I have been using this combo for now 14 months without any issue regarding AF

AF is sharp and fast, of course at f8 you need light

Just be sure that the size of the AF sensor is adapted to your target the DOF at 560mm being narrow
 
First thing I would do is examine the out of focus images at 100% to see if any part of the image is in focus. If something is in sharp focus and it is not in the area in which the camera was showing focus, then, yes there is some problem with your AF.

If nothing is in sharp focus, then it is not an AF problem. Rather, it is likely motion blur which is very easy to get at 560mm on an APS-C sensor.

There are potentially numerous other issues as well. For example, if you were focusing on something near the edge of the frame, your lens could be slightly de-centered in which case, the AF is correct and the lens simply can't get a fully sharp image in that portion of the frame.

Unfortunately, problems like this frequently take lots of testing to identify accurately.

Start with a static target, a tripod, self timer and a high shutter speed. Those will at least eliminate motion blur from the factors. Then you can experiment with shooting with the focus point in the center and at the edges of the frame.

Good luck.
 
baobob said:
Just be sure that the size of the AF sensor is adapted to your target the DOF at 560mm being narrow
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I also found that AF is faster and more dependable if you use Zone autofocus (more points to choose from for the camera software). Not always possible, but often is a good choice.

Alternatively, as baobab said, make AF points bigger.

Noticed with just 400mm (no 1.4) in low light.
 
I don't use the 1.4 TC but I do use the 2x TC with the 100-400 and I've been pretty happy with it.

bfdd76d9bfe1429da2dad27aff497b1f.jpg
 
First with the 1.4 TC, your lens isn't a 540 mm lens but an 840 mm lens (400 X crop factor (1.5) X 1.4 TC). So using the formula of one over the focal length to determine minimum shutter speed, you need at least 1/840. I'd set the shutter speed to 1/1000th or better to get sharp photos. If I were using your lens, I'd set the shutter speed to at least 1/1500 or faster. And I'd be using a monopod.
 
I have been successful for tack sharp shots at 400mm +1.4x ext OIS on at 1/30 sec, handheld without problem 50% tack sharp at least

Switching OFF the OIS is not relevant here

The OIS is amazing
 
rsn48 said:
First with the 1.4 TC, your lens isn't a 540 mm lens but an 840 mm lens (400 X crop factor (1.5) X 1.4 TC). So using the formula of one over the focal length to determine minimum shutter speed, you need at least 1/840. I'd set the shutter speed to 1/1000th or better to get sharp photos. If I were using your lens, I'd set the shutter speed to at least 1/1500 or faster. And I'd be using a monopod.
Click to expand...
 
Vic Chapman said:
rsn48 said:
First with the 1.4 TC, your lens isn't a 540 mm lens but an 840 mm lens (400 X crop factor (1.5) X 1.4 TC). So using the formula of one over the focal length to determine minimum shutter speed, you need at least 1/840. I'd set the shutter speed to 1/1000th or better to get sharp photos. If I were using your lens, I'd set the shutter speed to at least 1/1500 or faster. And I'd be using a monopod.

--
Given the choice between excellent equipment and great skill, I'll go for the skill every time.
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What is the point of having OIS then? Plenty of users shoot the 100-400mm + TC at around 1/60 - 1/125 and full zoom for sharp images.

Vic

--
The sky is full of holes that let the rain get in, the holes are very small - that's why the rain is thin.
Spike Milligan. Writer, comedian, poet, Goon. 1918 - 2002
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i have images that are tack sharp at 1/30 (w OIS) and images that are blur at 1/1000 sec.

i also have images that are all blur even though i ensure focus and also images that are sharp at the wrong places due to the shallow DOP at 400mm or wrong focal point

conclusion: this is not a pick up and shoot and all pictures are as expected kinda lens.

it needs practice and experience with it to know you can get out of it.

not like say the 35/2. just mount and shoot and you pretty much get what you want at almost every shot.

this is the only fuji lens that i have that i went for practise shoots...like 200-300 images in an hour or less just to shoot fast and figure what is needed to get the best image. and never downloaded the images. just practise.

--
surge
 
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nikkor35f2 said:
Vic Chapman said:
rsn48 said:
First with the 1.4 TC, your lens isn't a 540 mm lens but an 840 mm lens (400 X crop factor (1.5) X 1.4 TC). So using the formula of one over the focal length to determine minimum shutter speed, you need at least 1/840. I'd set the shutter speed to 1/1000th or better to get sharp photos. If I were using your lens, I'd set the shutter speed to at least 1/1500 or faster. And I'd be using a monopod.
Click to expand...
Click to expand...
Click to expand...
 
Vic Chapman said:
rsn48 said:
First with the 1.4 TC, your lens isn't a 540 mm lens but an 840 mm lens (400 X crop factor (1.5) X 1.4 TC). So using the formula of one over the focal length to determine minimum shutter speed, you need at least 1/840. I'd set the shutter speed to 1/1000th or better to get sharp photos. If I were using your lens, I'd set the shutter speed to at least 1/1500 or faster. And I'd be using a monopod.
Click to expand...
Click to expand...
 
twan said:
I'm using this combo but i have the feeling that auto focus is a bit inconsistente.

I took pictures at 400 mm + 1.4 that were perfectly sharp and others at the same moment where the focus was just a bit off. Does this sound familiar? I cannot explain this.

I had the same issue with my X-T1. It makes me unsure about the use of the 1.4
Click to expand...
Might be worth posting some samples with exif. It's hard to understand if or why there is a problem with sharpness without see examples of where the problems exist.
 
Recall that image stabilization doesn't freeze the subject but the fore and background. You can't shoot BIF's, or wildlife moving around quickly at a 1/30 sec; that bear chasing you will only be a blur if you don't have a fast shutter speed.

So I'm going to give you a link, go to the 6th picture counting down and look at the shutter speed the guy shot with for the hawk in flight.

https://www.dpreview.com/forums/post/60698624

Now go to this guys photo and look at the eagle in flight, see how slow his shutter speed is and how soft the image is, he would have been better off with a much faster shutter speed - no OIS to the rescue: [Third photo down]

https://www.dpreview.com/forums/post/60689305

Go through the Nature and Wild Life forum here at dpreview and look at shutter speeds used for wildlife, you'll see they are very fast.

--
Given the choice between excellent equipment and great skill, I'll go for the skill every time.
 
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Shockwave said:
Switching off the OIS might be relevant for higher shutters maybe. I.e. over 1/1000. I'm not sure if it can cause problems when the shutter is fast enough, I'm guessing here so I might be completely wrong.

The other question is how well OIS works in combination with the 1.4x converter. Obviously it works well with lens alone, but perhaps there are issues with OIS using the converter that create problems.

As mentioned, I'm not saying these emphatically, I'm just surmising what potential issues there could be.
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Maybe, but I've never seen evidence of OIS introducing issues with the TC attached in any of the countless images I've taken with that combo. To be honest, I've also never bothered to switch OIS off regardless of the FL I'm shooting with that lens... with or without the TC attached. Not saying that there might not be something to that issue, but it's never bitten me -- and the 100-400 is arguably my most used lens.

So, I'm not going to recommend one path or the other here. Only stating my own experience which suggests that leaving OIS on may have little or no impact regardless of shutter speed. At least that's been my experience and I'd encourage folks to do their own evaluation and share their results.
 
Jerry-astro said:
Shockwave said:
Switching off the OIS might be relevant for higher shutters maybe. I.e. over 1/1000. I'm not sure if it can cause problems when the shutter is fast enough, I'm guessing here so I might be completely wrong.

The other question is how well OIS works in combination with the 1.4x converter. Obviously it works well with lens alone, but perhaps there are issues with OIS using the converter that create problems.

As mentioned, I'm not saying these emphatically, I'm just surmising what potential issues there could be.
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Maybe, but I've never seen evidence of OIS introducing issues with the TC attached in any of the countless images I've taken with that combo. To be honest, I've also never bothered to switch OIS off regardless of the FL I'm shooting with that lens... with or without the TC attached. Not saying that there might not be something to that issue, but it's never bitten me -- and the 100-400 is arguably my most used lens.

So, I'm not going to recommend one path or the other here. Only stating my own experience which suggests that leaving OIS on may have little or no impact regardless of shutter speed. At least that's been my experience and I'd encourage folks to do their own evaluation and share their results.
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I agrre

Moreover shooting with a 560mm FL needs some learning before. Both AF and AE are much more instable within the frame than when shooting say at 55mm

The DOF is alwaus narrow and due to the "false" perspective view (collapsing of true distances) the risk that the AF sensor catches some fore/back ground is much higher resulting in unsharp files

Also it is essential to remember that the Fuji does have have crosstype AF sensors but only vertical ones, which can also becomes a greater issue at 560mm than at 55mm

A way to check that is to focus holding camera with a45° inclination from horizontal.

To check for possible hardware issue, a systematic one per one factor shoul be done using atarget where no confusing factor could be present so better to choose for exemple a roof or a wall with bricks
 
Just take a look at these 2 pictures. I'm not sure why the Lynx is not sharp in the first picture



8d31bdf9b2144e9199e933e050df9b3a.jpg



7ac5aabaa7d048e89e501e3062d41c77.jpg
 
Vic Chapman said:
nikkor35f2 said:
Vic Chapman said:
rsn48 said:
First with the 1.4 TC, your lens isn't a 540 mm lens but an 840 mm lens (400 X crop factor (1.5) X 1.4 TC). So using the formula of one over the focal length to determine minimum shutter speed, you need at least 1/840. I'd set the shutter speed to 1/1000th or better to get sharp photos. If I were using your lens, I'd set the shutter speed to at least 1/1500 or faster. And I'd be using a monopod.
Click to expand...
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twan said:
Just take a look at these 2 pictures. I'm not sure why the Lynx is not sharp in the first picture

8d31bdf9b2144e9199e933e050df9b3a.jpg

7ac5aabaa7d048e89e501e3062d41c77.jpg
Click to expand...
Maybe simply a little more sharpening?

50699ed751be43d4a36198ee12dc9bc3.jpg





This one is also sharpened but is mis-focused IMO (on foreground rocks).

8626f1aee4a641e8a974f38f81f41bb6.jpg

Vic

--
The sky is full of holes that let the rain get in, the holes are very small - that's why the rain is thin.
Spike Milligan. Writer, comedian, poet, Goon. 1918 - 2002
 
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That is truly unfortunate as although they're both good the second photo is outstanding.

From a quick look it appears the camera/lens was front focusing in both but certainly in the first photo. Look at the small tree in the bottom right corner and it appears to be much sharper than the lynx.

What AF mode and what size AF box? I don't see any reason for this but did you half press focus and then recompose to take the shots?

Bob
 
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