zooming into Letus Ultimate ground glass when using a prime lens

Generally when using a 35mm adaptor Prime lenses are recommended. Mainly because they are generally cheaper and more importantly faster.

The fastest prime lens I own is an F1.2 Nikon. But generally mine are around f1.4 up to f2.

Zoom lenses are always slower by necessity as they cover different focal lengths. There are some awesome zooms out there. I own a Nikon 17-35mm F2.8 a 80-200 f2.8 and a Sigma 28-80mm f2.8. As you can see these are all f2.8. Cheaper zooms in this focal length are slower, around f3.5 or higher and on the zoomed end around f5.6. Now this is fine for some situations but with adaptors you need all the light you need.

So if prime lenses are what most people should use then you get the problem of fixed focal length. 50mm is 50mm etc… So you place your tripod with camera on it, you like the shot but you need to tighten it, with a prime lens that means physically moving forward! A bit of a pain! Also, when shooting interviews and you need to tighten the frame during a question you have to change to a longer lens or again move forward (the latter is not really an option unless you are on a dolly and track, as I did on Anorexia Part 4 and 5)

Now the great thing about the Letus Extreme and Ultimate (and I hear the SGPRO and BREVIS FLIP) is you CAN zoom a bit into the ground glass to change the frame of the shot, of course the out of focus bokeh doesn’t increase as it would when zooming in on the actual 35mm lens but it does change the shot size.

With the Ultimate I have found the loss of resolution when zooming into the ground glass all the to the end of lens to be impossible to actually notice.

I was working on a documentary in Ireland last week and whilst filming some interviews in a very bland room I did a lot of zooming in to change frame sizes. Below are some grabs to show this off. The lens was a Zeiss f1.4 85mm shot wide open.

Shooting of course on an EX1...instead of giving the focal length of the Fujinon lens am going to refer to the Z number in the viewfinder and LCD screen. Here we are obvious pulled out wide
This is about Z50. The reason the edges are soft is this is the fall off the 85mm Zeiss lens. The actual true 35mm frame is way tighter. The Letus is capable of showing a much wider than 35mm frame but be careful not to zoom out too much. You can also see there is more black on the left of frame than the right. My Ultimate is out of alignment with the EX1 sensor. There is an XY adjustment inside the Ultimate. A bit fiddly but once done it shouldn’t need to be done again. A great feature. Please visit Steve Cahill’s blog to see the inside of the Ultimate and the XY adjustment. This feature is great news for HVX owners as the sensor is famously not dead centre and has caused issue with 35mm adaptor users for a while.
We are at Z69 here. just past the edges of image fall off. There is slight darkness to the edges but am pushing the limits of how wide I can go here. Recommended Zoom on the EX1 is around Z77 to avoid fall off and get an accurate 35mm frame. I had a proper monitor with underscan which showed the complete recorded image. The LCD and viewfinder of the EX1 is annoyingly not underscan so don’t do what I did without a monitor. I wanted a wider shot and the slight falloff is actually quite appealing to the eye so I shot a lot at Z69.
This is about Z97 on the Fujnon lens. I have not changed lens at all. Notice the out of focus blue flag is identical in it’s bokeh to the Z69. If I had changed to a longer lens this would have been a lot more out of focus. But the resolution is identical when viewed on a full HD monitor. Incredible flexibility for talking heads and other shots. With my old M2 and Brevis the Zoom had to be exactly spot on, taped down and never changed or edge sharpness is badly effected.

The value of the ability to zoom into the ground glass without losing resolution or focus should not be underestimated. Sure for dramas not so much as you have time to change to a different prime or move the camera, but for documentary and other work it is an absolute joy. When I discovered this with the Extreme I was over the moon. Now with the Ultimate it is even sharper.

But do remember, if you have no monitor, keep the zoom to around Z75-77. Wider and you risk vignetting or edges. If you have a monitor with underscan then look at that and use your eyes to judge.


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  1. Thanks for the tips Phil. I have a Letus Extreme, not the Ultimate. Does the same rule for zooming and sharpness apply to the Extreme as well, or is it better with the Ultimate? On my Extreme the centering is off too, but is this adjustable as in the Ultimate?

    Thanks for all the great work and help for fellow EX1 and Letus owners out there.

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