The best I've done! A1+Letus35A

rawfa

rawfa

Veteran
Hi guys,

Since I bought the A1 I've been doing an extensive batteries of tests to prepare for a feature I'll start shooting soon. On my quest for the best I've wondered many times if the A1 with it's beautiful DOF and bokeh really needs a 35mm adapter. Yesterday I was determined to answer this question, so I spent the entire afternoon testing the A1 with and without the letus35A. My thoughts are the A1 doesn't NEED a 35mm adapter, because it's right out of the camera footage is already amazing...BUT once you actually put a 35mm adapter on this already amazing camera (with the RIGHT LIGHT must I stress) you enter an entirely new dimension.

check it out (shot with a 28mm, no CC done):

http://rapidshare.com/files/13592917/The_Two_Towers.wmv.html

I'm sorry for the bad compression...it's actually the reason there's so much grain. If somebody can give me a few pointers on how to obtain the best quality with wmv I would be deeply appreciated.
 
rawfa, thanks for the post. the colors look great. the grain looks an awful lot like an 35mm adapter's ground glass when it's not spinning. is the letus' gg spinning in the shot? or is the grain introduced post-compression?
 
There might be a LITTLE bit of grain from the adapter on the original footage, but I can assure you the compression puts A LOT of grain on the footage you are seeing. I would like to hear from some compression expert to find out what are the best settings to export wmv.
 
Of course, I haven't seen this footage on an HD monitor, so I can't really say for sure what's up. I'm seeing it right now on my PC monitor and a SD TV set I have plugged in on my pc.

Disject said the footage looks kind of muddy...that is something I have to ask the 35mm adapter pros. I've been told that I should use ND filters so that I don't have to close the lens down too much...so I used 2 ND filters (each had intensity #3). Do you think all the extra glass in from of the lens might be interfering with the quality? I see Disjecta's footage and it DOES look more nitid. But the problem here is that when I close the lens too much I start to see dark splotches. Another thing that might have increased the grain is the weight of the lens I was using. It was a very heavy sigma 28mmf1.8. I don't think the letus has enough spinning power for that. Anyway, it's like I said, I'm doing all the tests I can before I start shooting for real. I would REALLY appreciate some constructive criticism/help, specially from people who are more experienced with 35mm adapters.

Tomorrow morning I'm going to the same place to make some more tests. So, if you guys could post some more useful info that might help me improve the quality it would kick ass. One thing I know for sure, I HAVE to get a field monitor. The LCD on the A1 is absolute crap for stuff like this.
 
i'm not familiar with the letus, but the grain i see, which seems very fine and detailed, is not indicative of typical compression. i do see some signs of the spinning ground glass by way of some moving splotches, which definitely looks like compression -- the weight of the lens impacts the spinning gg in the letus?also, there is some vignetting in the footy. can you zoom in further?

the reason you'd want to use nd filters up front is to keep the aperture as far open as you want to maintain the depth of field you're looking for. closing the aperture on the 35mm lens will widen the depth of field, so nd filters, under bright conditions, will let you keep control of the aperture setting up front. it is probably more sensible to use the iris and nd's on the a1 as this will minimize extra glass and maintain the dof created by your 35mm lens/adapter.
 
henry cho said:
the reason you'd want to use nd filters up front is to keep the aperture as far open as you want to maintain the depth of field you're looking for. closing the aperture on the 35mm lens will widen the depth of field, so nd filters, under bright conditions, will let you keep control of the aperture setting up front. it is probably more sensible to use the iris and nd's on the a1 as this will minimize extra glass and maintain the dof created by your 35mm lens/adapter.
Click to expand...

Yes, that I already knew, which leaves me in a bit of a pickle. I'm thinking the 2 ND filters that are having some negative effects on the image. Today I'm going to try to control the light all on the lens (as much as possible, because like I said, when I close it up to 20 something f I start seeing dark splotches). I'll let you guys know latter.
 
Btw, once I solve these issues I'm gonna go back to the same place and shoot this exact same shot. I find this composition really beautiful and the light at that time of the day was just priceless.
 
Ok, here is a quick montage of my tests from yesterday:

http://rapidshare.com/files/13894673/Forum_in_the_morning_2.wmv.html

I'm still not happy with the results. So, let's hear what you guys think that might be wrong. I didn't user any Nd filters this time and it looks like it really improved the "muddyness" but I can still see grain.

I actually want to go back to this same spot at the same time I made the first test (sundown). But it's kind of a waste of time trying to make any more tests basing my image monitoring on the A1's lcd upside down. So, today I'm going out to look for a field monitor.
 
I was also wondering if anyone has developed a custom preset and camera settings that maximize the A1's image quality when used with the letus.

I shot everything with a shutter speed of 1/50. Maybe if I increase the shutter speed it at least might minimize the grain.

As for sharpness and good color reproduction, there must be a preset combination that can take care of that. I notice that colors tend to be a bit flat with the letus.
 
coffee said:
rawfa,
the first few shots look pretty good but i wouldn't shoot a feature with this adapter as you're planning.
Click to expand...

Yes, that is actually the purpose of these tests. I'm coming to the conclusion that it can be too much of a risk. Besides the light resolution loss is just too brutal. The letus loses f1.5, my fastest lenses lose f1.8 (IF I'm able to always shoot wide open), the A1 wide open is f1.6...BUT I have to zoom in to be able to to film the letus's interior, so the A1 reaches f2.2. So, we're talking about a f5.5 light loss!!!!

To be completely honest I'm actually thinking about selling all my lenses, letus, achromat, etc and buy a merlin. I think it'll suit my needs better for the feature. Anyway, more tests to come.
 
The major difference is the simple fact that the LetusXL replaces the stock lens and mounts directly to the camera. That may actually help with reducing CA as there is less glass to go through.
 
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