Is it really better to not half-press to focus with the Fujifilm X-Pro 1?

Question

Fujifilm's new camera uses contrast-detect autofocus, and the current Internet hand-wringing is over whether this is a horrible critical flaw or not. As often happens in such discussion, a bit of street wisdom has arisen: it's better to just push the shutter the whole way. For example, this blog comment:

AF speed on the XPro isn’t that slow, the problem is that most people use it as they would an SLR/DSLR for focusing, i.e half press the shutter and wait for AF confirmation then press the shutter all the way, in most cases with the XPro and the X100 you don’t need to do this.

And there's at least one thread on DPReview, but as characteristic for such discussions, there's a lot more smoke than fire.

The X-Pro 1 manual says nothing about this, and in fact says:

S (single AF): Focus locks while the shutter button is pressed halfway. Choose for stationary subjects.

In my experience, if the subject is stationary, the half-press method works as it always does, and if it's moving the full-press method isn't as good as using AF-C (continuous autofocus). I've used plenty of point-and-shoot cameras as well, which of course use contrast-based AF, and the half-press focus lock has always served me well.

But then, a lot of people are saying this is a big deal. Is there any reasonable basis, or is it just wishful thinking?

Asked by mattdm

Answer

No, it is not. There is nothing magical about not waiting at the halfway point.

What you read is silly, as if waiting would make the focus take longer or something. It does not work that way. You can press all the way as fast as you want and you'll get a shot in focus or not. The longer you wait at the half-press (in AF-S) mode or before fully pressing (in AF-C mode), the higher the probability the shot will be focused. Waiting too long might make you miss action but it won't make the camera miss focus.

Note, having an X-Pro1 one in hand and, for all I tried, I cannot see how not waiting at the half-press can improve focus.

Answered by Itai

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How does the new layout used in Fujifilm X-Pro1 sensor improve image quality?

Question

One of the allegedly big advantages of Fujifilm X-Pro1 is its new color filter array layout, which does not require anti-aliasing filter in front of it. In theory, this could mean notable improvement in perceived sharpness and details. Also, Moirè effect should be avoided with the reduced repetitiveness in filter pattern.

Are there any image comparisons available taken with the X-Pro vs a conventional Bayer sensor DSLR with similar specs (APS-C around 16MP), showing how these advantages work out in reality?

Asked by Imre

Answer

In contrast to the standard 2x2 bayer pattern the X-Pro 1's sensor uses a 6x6 pattern (see this link for images)

R,G,R,G,R,G        G,B,G,G,R,G
G,B,G,B,G,B        R,G,R,B,G,B
R,G,R,G,R,G        G,B,G,G,R,G
G,B,G,B,G,B        G,R,G,G,B,G
R,G,R,G,R,G        B,G,B,R,G,R
G,B,G,B,G,B        G,R,G,G,B,G

The new pattern results in every horizontal and vertical line being covered by all three photosite colours, the lack of which is the main source of moire in bayer pattern sensors. They combat this by using an anti-aliasing filter to (slightly) blur the image to ensure that all lines will hit all three colours. The lack of this blurring in the image that hits the X-Pro 1's sensor results in the potential for increased sharpness and image quality, which seems to be born out in reviews, see here and here

dpreview allows you to compare the X-Pro 1 to a wide range of cameras (shooting the same test scene) here.

Answered by Steven Cunningham

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Why aren't the electronic bright lines for framing in the X-Pro 1 viewfinder more accurate?

Question

The Fujifilm X-Pro 1 has a viewfinder which can switch between an electronic mode and an optical mode with an electronic overlay. One of the key features of this overlay is a "bright frame" — the optical finder shows a good deal more than the expected coverage area of the lens, and the bright line is supposed to show the actual frame.

But, in my experience, the frame line is drawn much too small — there's something between 5-10% off each side. Some of this is surely to cover for the parallax error (since it's not a through-the-lens finder in optical mode), but it seems like Fujifilm could have made the tolerances a little closer. As it is, I'm getting used to cropping in post — or switching to the EVF for critical composition, which is annoying, since the optical view is so much nicer for catching fleeting expressions.

I understand why lower-end DSLR viewfinders don't offer 100% coverage, as there are considerable and obvious savings in size, weight, and cost. But in this case the viewfinder shows a considerable margin outside the line: the overall finder is more than 100%. Since the bright frame is drawn electronically, why isn't it drawn to more accurately match the field of view of the mounted lens?

Fujifilm has clearly put a lot of work into the design and photography-focused user interface of this camera, of which the hybrid viewfinder is a centerpiece. So, surely the viewfinder frame lines work this way for some good reason. What is that reason?

Asked by mattdm

Answer

You can move your head around, and the frame will line up differently depending on your exact point of view. And wearing glasses, the frame will seem even smaller than without - because your eye is further away. Cropping is far easier than synthesizing something you thought would end up in frame, but actually didn't.

The viewfinder on a rangefinder camera should not be considered a device for exact framing, but rather choosing the direction of shooting. The bright frame shows you what's certainly covered. The expensive Leica M9 exhibits similar behavior.

Another issue is that the focal length of a lens is only approximate, with 5% variation not too uncommon. To make matters worse, adjusting focusing distance affects focal length on most of photographic lenses.

It would be possible to craft a more exact viewfinder if the human photographers had a standardized viewfinder-to-eye mount and lenses would report their actual focal length all the time. As long as these issues remain, it's better to err on the safer side.

Answered by Imre

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Can I change the Fujifilm X-Pro 1's viewfinder magnfication manually?

Question

The Fujifilm X-Pro 1's optical viewfinder mode automatically switches magnification to match the prime lens mounted. There's a "bright frame" electronically drawn as a heads-up display showing the area of the actual frame.

I have the 35mm lens mounted. When I picked up the camera a little bit ago, I discovered that the view through the finder was wider than it has been in my previous few days of using the camera, and that the bright line rectangle was smaller than I was used to. It seems to have switched to a wider view.

After puzzling at the controls and the manual for a while, I couldn't figure it out. I eventually unmounted and remounted the lens, after which everything was back to normal. But the camera seemed to always "know" the right focal length, as it drew the bright frame appropriately.

How did the camera get into this state? A glitch, or something I inadvertently changed? Is it possible to do on purpose? (I can see an advantage in some situations in having less magnification, in order to see more of the surrounding situation.)

I've searched the manual, but found nothing about this. (Unfortunately, the manual is both poorly organized and full of gaps on many points.)

Asked by mattdm

Answer

It seems you pushed the lever that switches from the OVF to the EVF for more than 2 seconds. Doing so will bring the magnification glass on top of the OVF. Try pushing it again for more than 2 seconds to put it back in the other position. That magnification glass is useful for the other lenses...

Answered by sebastien.b

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