jan van daalen
Well-known member
Hi Boogie,Hi Jan,
How old is granny, would you say?
I had to look that up in the "Tale of...." and it is 1966.
Hi Boogie,Hi Jan,
How old is granny, would you say?
672808 👍Boogieshrewm post 39,
What is the production number of grandmother 7x35?
Gijs van Ginkel
One year older than me!Hi Boogie,
I had to look that up in the "Tale of...." and it is 1966.
Cool. I will look up your review.Boogieshrew,
I found the same production year as Jan (not surprising since we probably use the same source). In the test of 7x35 Leitz-Leica Trinovid binoculars in comparison with the Retrovid on the WEB-site of House of Outdoor you can find a test of that particular sample from 1966 (I borrowed that sample from Jan at that time for the investigation of the 7x35 Retrovid, actually the one you have now).
Gijs van Ginkel
Here we have an example of Gijs' tests which makes me wonder about his procedures, accuracy and - ultimately - usefulness for us.
Now come on Gijs, I'm sure you can do better.Renze, post 47,
Since I am interested in the historical development of binocular optical performance I sometimes make the choice to investigate also historical /older binoculars. I read from your post that this does not interest you in the least, but I can understand that, everybody has his/her hobbies or fields of interest.
When Jan van Daalen bought the 7x35 Retrovid we went together to the Kijkerspecialist in Holland, a well-known and very able repair specialist, who took the Retrovid apart for us, so we could get a look insight to get an impression of its construction.
It seemed interesting to investigate next to the Retrovid also older Trinovids and Jan had a few, so they became also part of the test.. The binoculars were cleaned as far as I could and then they became "victims"of the test. In your post you do not pose one question, but since you do not like or do not believe the results you question our measuring methods. You are free to do so, but it is in my opinion not very elegant and gentlemanlike.
For your information: the test procedures we use and the optical measurement techniques were judged by some binocular companies (and judged as being sound), the scientific papers in which the equipment was presented was judged by international experts, the standard procedure for judgment of scientific papers, not especially for binoculars but for ultramicroscopy, so we can measure spectra af single molecules. But that system is very sensitive and is also equipped for measuring the light transmission of binoculars. The other data were collected by measuring different parameters using the proper equipment as described in different physics textbooks about optics and optical equipment.
If you look into older binoculars, and I have shown that over and over among others at presentations for the Binocular History Society, you will be able to see, that in older systems light transmission values are very low as compared to modern optical systems.
Gijs van Ginkel
Started this at #51,Side by side with the 8x32s, one can appreciate the brightness of the Retrovid 7x35. For the same physical size, you have a brighter and wider image.
Gils helped with brightness data,UVHD+ 832 FOV @ 1000 yds = 404', @ 50 yds = 20.2
Retrovid 735 FOV @ 1000 yds = 421.7', @ 50 yds = 21.085.....
Brightness? Gils do we know for these two?
I think it's a novelty item, but also a good binocular, and if you want to spend the money, no problem. On the other hand, I would expect a sealed binocular with a large focus knob be a safer and more appropriate choice for a birding trip.I think if anyone is a Leica-fan-boy in anyway, they owe it to themselves to see the 7x35 in person and decide where it fits in their lineup. I have three Leica's already and have ordered in a 4th with the 10x32, so might have to get the 7x35 too (my 5th), from Duncan I am thinking in the Netherlands. But, I still have reservations----not optically----but more along the lines of; is this a 'birding binocular' or just a 'novelty' .... (which I consider to be the same for the original Zeiss dialyt )....
Worth a shot I suppose, as one can never beat the dopamine effect connected to opening up new optics boxes.jim
Hello Gijs,No Renze, I am waiting for your measured data.
Gijs van Ginkel