Comments on: FreshDV Hands-On Review - Brevis35 Flip Adapter (Part 1)

By: Matthew Jeppsen

Matthew Jeppsen — Mon, 11 Feb 2008 12:42:44 +0000

FYI Part 2 is up. Read it here: http://www.freshdv.com/2008/02/freshdv-hands-on-review-brevis35-flip-adapter-part-2.html

-Matt Jeppsen

By: dennis wood

dennis wood — Tue, 05 Feb 2008 20:36:22 +0000

And I couldn’t recommend a better team to tackle the problem :-)

By: Kendal Miller

Kendal Miller — Tue, 05 Feb 2008 05:06:09 +0000

Dennis,
I agree with you here. What we are trying to dispell is a lot of misinformation drawn by users, as you just pointed out, based on faulty testing and inconclusive research. Cheers :)!!

Readers,
Like I stated previously their is a lot of stuff going on in 35mm adapters across the board and the science of photography and optics and the physics of light can sometimes be confusing. Brevis adapter has some very compelling points, M2 has strengths, Letus has strengths like cameras each one has strong points and weak points. I suggest everyone step back and take a deep breath especially those over at DVXuser. When the jury returns with the data you may draw your conclusions as you see fit at that time. Let us process this data and present it in an accurate, thorough manner. We have full intentions of doing a comprehensive adapter test in the very near future.

By: dennis wood

dennis wood — Tue, 05 Feb 2008 04:23:48 +0000

Woops, that equation should have read:

-0.5 = -1 plus (adapter loss) ..for some reason the plus sign is getting left out whilst saving the comment….

The -1 figure is from the 50mm f1.4 lens that theoretically should lose about 1 stop when used wide open at f1.4

By: dennis wood

dennis wood — Tue, 05 Feb 2008 04:17:48 +0000

Kendall, to clarify, no one has claimed an increase in light. It’s just that in a dvxuser thread long ago the below equation was put forth by the Letus guys to describe an adapter’s system loss:

Total system loss = 35mm lens light loss adapter internal light loss

In the case of Brevis flip 50mm f1.4 lens losing about .5 stops of light with a 50mm f1.4 lens attached, (http://www.cinevate.com/images/lightloss.mov) the equation becomes this:

-0.5 = -1 adapter loss
Solving the simple equation means that the adapter loss = 0.5 … a positive number!

I’ve always maintained this was an inaccurate way to measure light loss as if you do it, you must represent the Brevis adapter as gaining .5 stops of light…which clearly it does not. Instead what you’re seeing in your experiments is that the 50mm lens does not actually cause the 1 stop loss that it should. For that reason, I have been suggesting dropping the “adapter loss” equation and instead measure it as you guys have done, at f1.4, f2.8, f4 and f5.6 to establish the trend. This would illustrate that the Brevis with CF1Le is actually much more efficient than the other adapters out there when compared at f8. The difference in Phil Bloom’ shootout is in the order of 3 stops difference..a lot of light!

Keep in mind that the curve changes with CF2le, and CF3Le to reflect a bit more linear behaviour.

By: Kendal Miller

Kendal Miller — Sun, 03 Feb 2008 20:16:57 +0000

LOL ALban…THOROUGH NEWS!!! FreshDV TORTURE TEST!!! The image analysis is done and should be forthcoming. We have been spending A TON OF TIME (Read days) lately cracking the egg on the Brevis non-linear light response alot of users have reported seeing and many have drawn up as an increase in light. The information and test we conducted has never been seen or published before to my knowledge so you will definitely want to see it. One thing we do is thorough testing before publishing so thats the time delay. There is a lot of science and math at play here that frankly was very difficult for us to explain and research.

By: Alban Egger

Alban Egger — Sun, 03 Feb 2008 15:44:01 +0000

So when are wee seeing Part 2? Is that good news or bad news when it takes so long to “confirm results”??

By: Jipsi

Jipsi — Wed, 30 Jan 2008 00:55:17 +0000

Great article, looking forward to Part 2.

By: Matthew Jeppsen

Matthew Jeppsen — Tue, 29 Jan 2008 21:08:00 +0000

Part 2 will be out very soon, I just needed to double-check a few of the tests and confirm results we are seeing. Stay tuned!

-Matt Jeppsen

By: Rock Raines

Rock Raines — Tue, 29 Jan 2008 21:03:51 +0000

Whatever happened to part 2???

By: Dennis Wood

Dennis Wood — Sat, 26 Jan 2008 06:51:55 +0000

We’ve named the new quick-release the “Matt Jeppsen” edition :-)

By: Tobias

Tobias — Fri, 25 Jan 2008 23:56:13 +0000

Thanx alot for the review! I have an EX1 and a Brevis flip on it’s way. Looking forward to part 2…