letus ex and canon a1 help needed.

reem12

reem12

Veteran
1. hi all.i waswondering if someone who has the canon a1and letus ex could tell me if they had to make any adjustments to the back fofus on their letus to achieve infinity focus or should mine be pre set for my camera and if so what method did they use?


2.how far is everyone who owns the canon a1 and letus ex zooming in to get the full 35mm fov while avoiding any type of vignetting.my problem is that i'm not sure the canon a1 has actual z numbers to alert you on how far you actually zoomed in,if this is incorrect can someone please tell me how to go about it.thanks in advance.
 
reem12 said:
2.how far is everyone who owns the canon a1 and letus ex zooming in to get the full 35mm fov while avoiding any type of vignetting.my problem is that i'm not sure the canon a1 has actual z numbers to alert you on how far you actually zoomed in,if this is incorrect can someone please tell me how to go about it.thanks in advance.
Click to expand...

Go into the A1 function menu and you can change the setting to display the zoom number from 0-99 instead of the bar.
 
I did have to make a backfocus change - I originally did it just adjusting the lens mount out a tad - probably 1/2 a millimeter or so - I ended up doing a permanent job on the actual ground glass with help from Aaron at Letus Direct - I think there is also the option to have it set at the factory, which I believe was the original deal but with the lens adapters coming non-attached, I'm not sure if that is the case or if anyone is actually just slapping it on without having to make any backfocus changes.

Now I can flush mount the lens adapter and throw any Nikon lens on and have infinity read correctly.

As for zoom setting, I believe 78 is the correct Academy setting on the A1 according to Disjecta - I'm actually testing this for myself in the next couple of days - by about 71 I'm safely zoomed in on the ground glass, but at that point, I may not be mimicking actual 35mm frame.

Other than that, the Letus is a breeze and joy to work with.

cheno
 
you may see Z71 on your lcd ascreen as looking fine, but take a look at the full frame on your laptop or computer monitor, with the overscaned image, you will see plenty of vignetting. Zoom in further :)
 
Papa What setting would you recommend with the Canon A1? I use 72-73 but I do see Vig at 71 or lower. Is z78 the proper academy setting on the a1?
 
oh my opologies for not clarifying.the zoom issue i had was on the canon a1.i didn't no how to pull up the zoom numbers on my camera so i took jades instructions and went to the function on my canon a1 and switched from the bar to the zoom #,now it tells me the exact # of how far i'm zoomed in.
 
Zoom 78 is 35mm framing.

for the backfocus, all i did was loosen my nikon mount, with the lens attached, focused at inifinity. The more telephoto the lens being used, the more accurate your adjustments will be.

Now with your telephoto lens attached, set at infiniti, gently push in, or out, your lens mount piece until you see a sharp image at infiniti. Then i just tighten the screws down and im set to go. Now my measuring tape readings are accurate!
 
PaPa said:
Zoom 78 is 35mm framing.
Click to expand...

When I am at zoom 78 on my A1 I stop down to a 2.6. Dennis just posted that the Brevis flip is full frame at Zoom 73 which can still be 2.4.

I guess the Imaging element projects a slightly bigger image. It is not much, but every little bit of light helps I guess.

I really wish there was the ultimate, comprehensive shootout that spelled all of this out.
 
the brevis is at 2.4?/ YES w000 hoooo, finally my answer! i have asked that a bazillion time but never got a straight answer.

jeezz, horay! Now im glad i have my letus, i wasnt sure if the brevis flip would lose less light due to less zoom in, but that .2 difference in a stop does absolutely nothing for me.
 
Papa, with the correct optics in place, we can finally provide the solid numbers you were looking for. The same zoom settings can be used for anything from an f3.5 28mm, to a 28mm-200mm f4 zoom lens. Total light loss including loss from a 50mm f1.4 lens is better than we had previously quoted...so about .7 stops. To say that I was very thrilled with the results of our engineering project would be an understatement at this point. Edge to edge sharpness on all the lenses tested is simply outstanding. The alignment system works flawlessy, even on our HV20 with an inherent CMOS misalignment of at least 10% .... this means no extra zoom-in for these folks.

We're quite happy with the overall weight of 2.3 lbs, retaining the interchangeable imaging elements, internal rechargeable power, and micro-collimation lens systems :-) I suspect ur past, present and future customers will be thrilled with the performance.
 
no i dont doubt that in the least.

i have always loved the brevis and used it many times, its just that since i purchase the letus extreme, my only only only concern is that perhaps the brevis with filp would provide less zoom in so i would get more stops of light! I just needed to know just HOW much more light i would get by the zoom factor, and if the difference is from F2.4 to F2.6, then i am glad i made the decision i made with the Letus. But if it were a half stop of difference, i may have had a change of heart and sold my letus for the brevis flip.

:) Go brevis!
 
i'm pretty much in the same boat with papa,although the letus is not condusive for most low end stabalizing system due to i'ts weight,which in actuality can be a plus for for i'ts rugged durability.overall,It's taken me going through 3 adapters to finaly be satisfied.thanks papa for the info.
 
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