Firstly, let me begin by saying that this is not a full review of the Brevis, there are loads of good reviews of the unit on the web so you should easily be able to find one of those elsewhere.
I most respects the Brevis is a great device, highly adjustable and works well. That being said though I don’t feel it’s fully compatible with my camera, the Sony EX1.
If you look at any of the videos I’ve shot with the brevis you’ll see that a lot of the footage is suffering from dark edges on the left and right sides of frame.
This is quite apparent in my video “Morston Mud” and can bee seen on the video thumbnail before the video starts playing where the large boat is laying on the beach.
Cinevate, the makers of the Brevis are very helpful and one of the best companies I have dealt with in terms of customer service and response times. Cinevate seem to be fully aware that pairing the Brevis with the EX1 can be a bit tricky and although they now sell a kit specifically for the EX1 they openly admit that the EX1 is not as ‘Brevis Friendly’ as Canon’s XH-A1 or Panasonics HVX200 / 201.
Apparently the lens on the EX1 has proved to be problematic for most 35mm adapters, I’m not entirely sure of the technical reasons for this but both Letus and Shoot35 have also had problems adapting their products to work well with it. Letus released a custom achromat for their ‘Extreme’ adapter which is very popular amongst EX1 owners. Unlike Letus though, Cinevate have not taken the route of producing a custom EX1 achromat and instead have produced a specific ground glass element to solve these issues called the cfXL.
I have to be honest and say that as much as I love the bokeh and the look of the Brevis for my personal videos, I would be very nervous about using it for a commercial project with my EX1 until I can start getting consistent results without the dark edges. It may be user error, or my lack of experience with adapters that’s causing my woes, hopefully I’ll be able to find a solution.
One interesting note is that Phillip Bloom has recently posted some footage on vimeo using the same adapter and said that he found z80 to be optimum, which is contradictory to Dennis Woods advice (Cinevate President) who said in one of his setup videos that z69 is optimal when using the EX1 and that the EX1 lens issues would start becoming more apparent at higher zoom levels. I always zoom in to the brevis by eye rather than relying on the numbers, but I can achieve full frame at z70 as suggested so these number do seem to add up.
I’m going to try shooting at a higher zoom level over the next couple of days, I’ll try and post some comparison images if I get any useful results.
[update - 31/10/2008]
I’ve been doing some expirements with zooming further in today and the one thing I’ve come to realise with the Brevis is that by changing the zoom you’re fighting against two separate side effects. At wider zooms (z70) it’s possible to get almost perfect edge to edge sharpness, which is the reason why Dennis from Cinevate recommended that setting, but this problem with the dark edges is more apparent at that setting and is a separate issue. By zooming past these dark edges to around z80 the edge to edge sharpness starts to suffer and anything further than z80 results in the focused area being confined more and more to the centre of the image.
I assume this is why Phil Bloom felt that z80 was optimum, the edge to edge sharpness is only just starting to be lost, and the dark edges are almost out of the frame. Any further in either direction and one of the problems starts to become more apparent than the other.
[update - 5/11/2008]
After shooting at Z80 for a while my feelings are that it still doesn’t result in good footage, the vignetting is still apparent in many shots, and especially when shooting in low light. Edge to edge sharpness is also badly effected at z80.
The only way I have been able to get usable footage is by shooting with the EX1 zoomed out to z60 and then cropping the footage in post. You lose resolution using this method though so although good for web video or 720p you cannot achieve true 1080p results.
I posted more info about the cropping method here