Tag: Optical Viewfinder

By V. Opoku

I shoot fujifilm exclusively; I use two X-Pro 1’s and a X100s for my wedding work and travels. This set up works for me, however there was a learning curve involved, as the concept of these X-Series cameras were different from the D-SLR’s that I was used to.

The biggest challenge I faced was learning how these cameras acquired focus, I spent hours online seeking relevant information and even more time applying what I read and testing things out. YES, they actually do focus, they just do it differently to my old D700 and a friend’s 5D2 I had right next to it for comparison.

As a result of the information I gathered and my personal experience over the last 8 months, I decided to put this article together and I hope that fellow X-Series users out there and those considering buying one of these cameras might find it useful, especially in regards to focus accuracy.

Like ZACK ARIAS, I believe that the Optical Viewfinder is a big deal on these cameras. The hybrid viewfinder is innovative and each mode serves a purpose, i.e for close ups where the Electronic Viewfinder is the better option. Nevertheless, I find myself using the Optical Viewfinder 90% of the time, I truly love it. The focus on this article will be focusing with these cameras (X-Pro 1 & X100s) with the Optical Viewfinder.

PARALLAX:

“The effect whereby the position of a object appears to differ when viewed from different positions. In this case, the different positions are the lenswhich is at the centre of the camera and the viewfinder window which is to the left and above the  centre of the camera.

 

 

VIEWFINDER WINDOW:

We have established that the viewfinder window is positioned to the left and above the centre of the camera, thus being positioned to the left and above the lens.

The viewfinder window (when in optical mode) is designed to have a larger Field Of View than whatever lens you attach to the camera body. Because the Field Of View of the viewfinder is larger than the Field Of View of the lens, you are able to see things that are outside your frame and not just what is inside it – the OVF is under inclusive.

 

CORRECTED AF FRAME:

 

The different positioning of the viewfinder window and the lens means that we have to overcome parallax when it comes to nailing our focus. To aid us in doing so, these Fuji X-Series cameras have a brilliant tool called “Corrected AF Frame” ; this is optional but I strongly suggest that you turn it ON and leave it ON.

 

BOX 1 : Represents the focus frame at infinity – This is where the OVF will naturally perceives focus to be.

BOX 2 : Represents the focus frame at the OVF’s minimum focus distance – the closest the OVF can focus before it hits the macro range. (This is about 2.6ft for the X-Pro 1 and about 1.6ft for the X100s)

This is how I have the Optical Viewfinder (OVF) set up in all three of my cameras:

 

 

My custom OVF displays have quite a lot of information overlay which I have become used to, however for the rest of this article, I will “turn off” most of these information and only “leave on” those which I believe are relevant to acquiring focus with these X-Series  cameras.

 

 

We are now left with a much cleaner looking OVF, with just the Focus Frame at infinity (BOX 1) and Corrected AF Frame (BOX 2) as well as  theDistance indicator on.

The distance indicator is pretty useful since the distance of our subject is used to calculate the amount of parallax compensation that is needed between the viewfinder window and the lens. So having an idea of how far or close our subject is can help us to acquire our desired point of focus with greater accuracy.

 

THE ESSENTIALS:

1. Due to the different positioning of the OVF and the lens, they naturally see focus at different points.

2. However, the camera has ONLY ONE REAL FOCUS BOX, which shows up at different locations within the OVF.

3. When we turn Corrected AF Frame on, the two boxes (BOX 1 & BOX 2) that shows up in the OVF represents the RANGE within which the REAL FOCUS BOX could be.

4. The RANGE  within which the REAL FOCUS BOX can be is BETWEEN infinity (BOX 1) and the focus frame  at the OVF’s minimum focus distance (BOX 2)

5. The RANGE for the X-pro 1 is infinity and 2.6ft

6. The RANGE for the X100s is infinity and 1.6ft

 

 

 

7. When we press the shutter down halfway to auto focus, the camera calculates the distance of our subject and a GREEN BOX appears diagonally between the RANGE.

8. This GREEN BOX is the REAL FOCUS BOX.

9. Exactly where the REAL FOCUS BOX appears within this RANGE depends on the DISTANCE of our subject – in other words, where the REAL FOCUS BOX appears between BOX 1 and BOX 2 depends on how far or near our subject is.

 

 

The GREEN BOX is the REAL FOCUS BOX – this is the actual point where the camera focuses the lens, and it will be located slightly below and to the right of where the viewfinder window perceives focus to be.

Remember that the viewfinder window and the lens are positioned at different locations –  and even though we are seeing our subject through the viewfinder window, we want our final image to be how the lens sees our subject. 

We want the focus point of the image we capture be where the lens focuses – the GREEN BOX is our parallax compensated FOCUS BOX, it sees our subject how the lens sees it, hence why it is the REAL FOCUS BOX.

The RED BOX (RANGE BOX) is solely for the purpose of this article and it will not show up in the camera.

Here is the same image as above but without the range box:

 

The distance of our subject is what determines where the REAL FOCUS BOX appears within our RANGE ; the distance indicator tells us how far or near our subject is, therefore knowing our subject distance is useful.

 

 

Let’s assume with an X-Pro 1 + the 35mm lens, when we press the shutter halfway, the camera calculated that our subject was 5ft away, and where the REAL FOCUS BOX  has shown up in the illustrations of this article is a representation of that, so where the GREEN BOX has appeared between the RANGE so far is because our subject is 5ft away from us.

What if our subject was 3.6ft or 12ft away? Where between the RANGE will the GREEN BOX appear?

 

 

With our subject at 5ft away, the GREEN BOX appears relatively central between BOX 1 and BOX 2.

With our subject at 3.6ft away, the GREEN BOX appears down to the right, away from BOX 1 much closer to BOX 2.

With our subject at 12ft away, the GREEN BOX appears further up and to the left, away from BOX 2 and much closer to BOX 1.

This demonstrates that the GREEN BOX moves diagonally between BOX 1 & BOX 2 ; and exactly where it appears between these two boxes depends on the distance of our subject.

 

What happens if our subject is further than 12ft away or closer to us than 3.6ft?

 

 

With our subject at 30ft away, the REAL FOCUS BOX will show up within BOX 1.

At 2.6ft away, the REAL FOCUS BOX will show up within BOX 2.

Why does the REAL FOCUS BOX appear within BOX 1 & BOX 2 at these extreme distances? Beacause :

BOX 1 : Represents the focus frame at infinity.

BOX 2 : Represents the focus frame at the OVF’s minimum focus distance – which is is 2.6ft for the X-Pro 1.

Remember the RANGE BOX? let’s go back to it:

 

 

The REAL FOCUS BOX can appear anywhere within the RANGE BOX – the GREEN BOX can appear anywhere between BOX 1 & BOX 2.

When our subject is further way, i.e 30ft from us, parallax is not an issue and the couple of inches between where the viewfinder window naturally perceives focus to be and where the lens naturally perceives focus to be is meaningless.

So with subjects further away, the REAL FOCUS BOX is more or less identical to BOX 1; the viewfinder window and the lens perceives the same REAL FOCUS POINT at far distances,  that is why the GREEN BOX  appears within BOX 1.

 

If our subject is much closer i.e 3.6ft, parallax becomes an issue and the couple of inches between where the viewfinder window naturally perceives focus to be and where the lens naturally perceives focus to be now matters; however at such a close distance, parallax is so great that you are better of switching to the Electronic Viewfinder.

If our subject was 2.6ft from us, the REAL FOCUS BOX is more or less identical to BOX 2, this is the closets the OVF can focus before it hits the macro range,  but parallax is great at this distance so use the EVF! The camera automatically switches to the EVF when one uses the macro function.

If our subject is at a midrange distance, i.e 5ft from us the REAL FOCUS BOX appears at the appropriate area between the RANGE BOX.

 

SUMMARY:

The camera’s viewfinder window and lens are positioned at different locations and as a result we have parallax.

The camera has only one real focus box, when you turn on Correct AF Frame, two boxes shows up in the OVF.

These two boxes represents focus at infinity and the OVF’s minimum focus distance – this gives us the range within which the real focus box can show up once the shutter is pressed halfway.

The distance of our subject determines  exactly where within the range that the real focus box appears.

When the shutter is pressed halfway, the camera calculates the distance of our subject, compensates for parallax and shows us where the REAL FOCUS is.

 

This same principle applies to any of the 25 different focus points that we can chose from in the middle 2/3rd of the OVF’s frame.

 

 

I used the middle focus point throughout this article for simplicity, however, this is how things should look when we select other focus points:

 

MOVING FRAMELINE:

When we press the shutter down halfway, the camera calculates the distance of our subject and compensates for parallax for both the focus frame and the frameline – this gives us an accurate representation of how the lens sees everything.

 

 

How much the frameline moves  down and to the right depends on the distance of our subject.

For a subject far away, i.e 20ft, the frameline moves very little, in fact if our subject is beyond 20ft, i.e 30ft, the frameline doesn’t move at all. The closer our subject is, the greater the movement of the frame line.

The closer our subject is to us, the greater the parallax, hence the greater movement of the frameline ; the further our subject is away from us, there minor the parallax, hence the little movement of the frameline.

 

DIFFERENT LENSES:

Each lens has a different Field Of View, however, the Field Of View of the Optical Viewfinder will always be larger than that of the lens attached to the camera. This is the same for the X100 and X100s albeit with a fixed 23mm lens.

 

 

CAVEAT:

The Framelines, are an approximation and just like the Corrected AF Frame and the Distance indicator, it is a tool to aid us. It might take some time getting used to it, but it is totally worth it and will become second nature in due time. The OVF is pure joy to use!

Here is a small selection of images taken under various conditions using the OVF:

V.

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