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Light transmission; Classic v Victory 8x56 (1 Viewer)

CharleyBird

Well-known member
England
If the simpler design of the Classic 8x56 with apparently less glass and coated surfaces would lead one to expect higher light transmission, how come the Victory with more glass to air etc actually achieves a slightly higher light transmission?

Is it down to the difference in coatings or design?



I was looking at the comparisons here:
http://www.allbinos.com/index.php?test=lornetki&test_l=174

and the zeiss reviews at the end of the article here:
http://www.zeiss.de/C12567A800347580/EmbedTitelIntern/Test_Pirsch_11-06/$File/Test_Pirsch_11_2006.pdf


Regards

Andy
 
Andy,

Coatings improvement is really the only possible explanation. BTW, the cutaway view at the Polish site is misidentified. It shows the older 8x56 Victory, not the 8x56 FL.

Henry
 
Henry,
Sort of on topic, have you seen a transmission plot for the FL? I am curious about the often reported cold or blue look to this binocular, and have noticed it myself, in comparison to other binoculars which are notably red and dim, like the Leica Trinovid. Is the FL really blue, or only true, which would seem relatively blue in a comparison?
Ron
 
Ron,

I haven't seen a transmission plot for the FL, but I think the photo images in post #30 from the thread below show the color bias history of the FL series pretty well.

http://www.birdforum.net/showthread.php?t=131853

My early 8x42 FL still appears more neutral to me than recent production, which might mean that in low light it's image could look a little dimmer to the dark adapted eye from lower transmission in the blue/green.

Henry
 
Henry,
Thanks, I remember that now, and that FL certainly looks the most color neutral of the bunch. That was real nice work. But, your mentioning that it's an older model, presumably pre-Lotutec, brings up another question.

My FL is Lotutec, and the coating on the outer lenses reflects a reddish orange. I would even say that, considering the FLs reputation for high transmission, the intensity of the reflection, often taken as a seat of the pants indicator of transmission, is surprisingly bright. This would seem, by reflecting red light away from the objective, to make the transmitted light skewed towards the blue.

I have never seen a non Lotutec FL. My question is, is the outer non-Lotutec coating reddish like I have described?
Thanks,
Ron
 
My FL is Lotutec, and the coating on the outer lenses reflects a reddish orange. I would even say that, considering the FLs reputation for high transmission, the intensity of the reflection, often taken as a seat of the pants indicator of transmission, is surprisingly bright. This would seem, by reflecting red light away from the objective, to make the transmitted light skewed towards the blue.

I have never seen a non Lotutec FL. My question is, is the outer non-Lotutec coating reddish like I have described?

Ron,

Here's a photo that shows the difference in the exterior surface reflection colors between my Lotutec 8x56 FL and early 8x42 FL. The 8x56 is on the bottom and the window reflection on the right comes the exterior surface. The eyepiece exterior surfaces show the same difference. That's what made me suspect that Lotutec might be the cause of the color bias difference, but the change could be coincidental.

It makes some practical sense to me to place the peak transmission in the green between 500 and 550nm rather than the more usual 550-650nm. The "green" choice isn't inherently more biased, but it may not be as attractive to the eye as a peak in the yellow/red. Bringing up the wavelengths between 450 and 550nm at the expense of red sacrifices the warm "golden hour" look, but at the same time it extends high transmission further into the blue/green where it really counts in low light. Of course, what I would prefer is perfectly flat transmission from 400 to 700nm.

Andy,

Yes, that's the FL.

Henry
 

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