I own a pair of Zeiss Dialyt 7x42B T*P.
Someone said:
Best Binoculars for Forest Birding -- Bar None! I own Swarovski, Leica, B&L Elites and Zeiss optics. I am an Ornithologist and professor with seven summers in Costa Rica under the canopy and decades of forest birding experience in the forested mountains of the eastern US. If you can get a pair of Zeiss 7x42's, don't miss the chance! 10x works better for field and water birding, but NOTHING beats the 7x42's under the canopy. Cheers!
I'm not sure when I bought them. Perhaps it was in 1995. This model was introduced in 1981 and was in production (West Germany) until 2004.
Here are some excellent reviews:
I see used pairs on Ebay for $400 to $500 in 2025. The new price was on the order of $900 in 1995.
The T*P designation is important. It indicates that the prisms (and perhaps other optical components) have the fancy Zeiss phase correction coatings. Early production of this model did not have these coatings. If you are shopping for a used pair, this is something to look for.
They are not roof prism binoculars. These are Abbe-König prisms, which are superior to roof prisms in that they need no mirror coatings and work entirely by internal reflection. (As a side note, a true roof prism design is called "Schmidt-Pechan".)
When I bought them over 20 years ago, they were the top choice alongside Leica. These days Swarovski seems popular. There are a lot more excellent offerings these days though, and if I was again serious about getting a really good pair of binoculars for birding, I would need to do my homework all over again. Very likely improved optical technology has made binoculars better in general and perhaps more affordable at this quality level
I spent a lot of time debating whether to get 7x or 10x. The 7x choice I made went for a bigger richer field and ease of use. It is unfair to say that 10x is better than 7x or vice-versa. The truth is that both offer advantages. The 7x has a nice wide field, the 10x may help you see important features.
The close focus distance with these is 10 feet. This was considered good at the time, and is still considered decent. However, if you get interested in looking at insects and lizards you are going to be frustrated..
I now have a pair of relatively inexpensive Vortex 8x32 "Diamondback" which have a 5 foot close focus distance and I really enjoy that aspect of them.
The Zeiss have an amazing 8.6 degree field of view. This makes them extremely pleasant to use. Compare this to the 8.1 degree field on my Vortex 8x32, which frankly is not at all shabby.
The Zeiss weigh 30 ounces. Just shy of 2 pounds. I have carried them on many trips, but I am enjoying the 16 ounce weight of my Vortex 8x32.
Eye relief is 16-18 mm -- I leave my eyecups permanently rolled down and use them all the time with eyeglasses and they are fantastic. I get the full field right to the sharp edge.
Tom's Bird Info / tom@mmto.org