For the most part the 7×43 unit is identical to the 8×43 externally with a few notable exceptions. The eyecup design of the 7×43 is longer (not away from the eyepiece but actually longer into the binocular body). The eyecups also fit more loosely than the 8×43 unit. Further, the antireflective coatings on the eyepiece are of a different color and “dimmer” than that of the 8×43. Objective color reflections are identical. The physical length and weight is identical between both binoculars. The diameter of the ocular lens is narrower on the 7×43 I am assuming because the 7x magnification design warrants it.
The only other external difference between the two configurations is in the focusing knob feel. The 8×43 displays about 1/8th of inch of play which does not change the focus point. The 7×43 does not display any play whatsoever and is extremely precise throughout the focus range. Focusing speed, direction and overall feel are identical between the two configurations.
Looking down the barrels from the objective side also revealed one key difference between the two models. The internal threaded baffling in the 7×43 unit is not as deep as the 8×43. They are “finer”. This, along with the eyepiece reflections I mentioned earlier will play a part in the optical performance comments I am to mention next.
Optically the 7×43 shares the same neutral color representation of the 8×43 primarily because of the specific formula of the antireflective coatings used in the ED3 design. As referenced in the 8×43 review this is a change from the slightly warm color bias of the ED2. The apparent field of view is narrower in the 7×43 design, 58.6 degrees versus the 65 degrees of the 8×43. In practical use I cannot tell much of a difference.
Eye relief for the 7×43 is listed at 20 mm. I have no problem seeing the full field of view with the eyecups fully collapsed. I do not wear glassed but because of my facial characteristics, large nose and relatively close-set eyes, I find that I need to use most binoculars with the eyecups in the fully collapsed position.
Close focus is right at 6 feet for my eyes.
In terms of the image, it is everything you would hope for in a high quality 7×43 binocular. The 440 foot field of view is expansive. Depth of field is also excellent. It does not give quite the “apparent” depth of field of a similarly configured porro prism model but the depth of field is still noticeably better than the 8×43 model. Very little refocusing is needed over a good percentage of typical birding distances. When you couple this with the faster focus of the ED3 design, one full turn from close focus to infinity, then you find a very easy combination to use out in the field. The larger exit pupil also comes into play here. One of the reasons I have always been so fond of the 7×40-something configuration is the large 6 mm exit pupil. The 6 mm diameter gives my eye more room to roam around the image. For the type of birding I primarily do, hawk watching mostly but also waterfowl, this characteristic makes using the binocular so much more comfortable.
Just like the other configurations of this model the image is exceptionally sharp mostly due to the use of extra low dispersion glass in the objectives but also because of the rest of the binoculars’ design takes full advantage of that ED glass.
Color saturation appears very good, again, probably in large part to the combination of ED glass and high quality antireflective coatings. Colors are well represented but do not necessarily have quite the “pop” that some of the ED3’s optical competition does (thinking Nikon and Leica in this case). Though not necessarily the case with the Nikon and Leica models I do find that many times a binocular with a specific color bias represents certain similar colors with better color saturation. Since the ED3 is fairly neutral in color representation I do not necessarily get “deep reds” or “brilliant blues” in much the same way as I would in other models. I often felt the same way about the Zeiss FLs that I owned for several years. The color representation was fairly neutral but specific colors might not necessarily have been as vibrant as competing models. I do remember an extensive explanation of this phenomenon with the FL in particular but do not have it on hand at the moment to continue the discussion further.
Apparent brightness is interesting for lack of a better word. In just about every condition I have tried these binoculars in the apparent brightness appears to be fairly equal between the 8×43 and 7×43 units. This really surprised me as I had fully expected the 7×43 to give me more of that overwhelming brightness that the 7×42 FL does even in comparison to the 8×42 FL. Before I expand on that issue let me also mention….
The sweet spot of image in focus and free of distortion is another issue worth discussing. This was something else that did not fully live up to my expectations. I do realize that different individuals have different preferences for what is “acceptable” in terms of the size of the sweet spot. Personally I find it directly related to the type and degree of distortion visible outside of the sweet spot. Some distortions can be distracting because of their severity while others can be distracting because they occupy such a large portion of the image. To put it simply, the size of the sweet spot in the 7×43 is smaller, to my eyes, than the 8×43. Conversely the amount of astigmatism in the outer edge of the image is too much for me to call the image “excellent” or “ideal”. I am not going to throw around estimated percentages with this one because I truly have not attempted to estimate it. I would estimate the 8×43 ED3 to have a respectably sized sweet spot in the range of 70-75%. I am sure if I actually tried to verify that in a scientific manner then the true size may actually be smaller but I am referring more to the perception of the size of the sweet spot rather than the actual measurement. Sadly, the 7×43 seems to be less than that 70-75%.
Depending on how you use the binocular this may or may not be an issue. When utilizing the binocular this past weekend I noticed the distortion but did not feel that it took away from the overall quality of the view. This past week when I had more time to sit down with it and literally “look for it” then I found it to be more objectionable. Further, when I compared it with two other models which both have exceptionally wide sweet spots then I became more aware of how much it took away from the potential total viewing experience. Coincidentally I had much the same experience when I first had my hands on one of the initial 7×36 ED2 units. After using the 8×43 ED2 for so long I immediately noticed what I felt was a smaller sweet spot and more distortion around the outer edge of the image.
All hope is not lost though. After making all of these observations I emailed Charles so that he would have the opportunity to clarify some of my concerns. From what he related many of my concerns are the result of this 7×43 unit being a prototype of the configuration. The production units of the 7×43 will have eyecups practically identical to the 8×43. The difference in eyepiece reflections was due to not having the full multi-coating on some of the lens elements…again a prototype concern not a production unit issue. The difference in internal baffling was also specific to the prototype and not something that will be evident in the production model.
I also have hope that the production unit will also have a sweet spot similar in size to that of the 8×43 model. My hope actually relates back to the 7×36 situation I mentioned earlier. This past week I had the opportunity to try out some of the 7×36 ED2s once again. I tried three of the units. All three had sweet spots notably larger than what I remember from that first production run. The distortion in the outer edge of the image was still different from the 8x43s but the size of the sweet spot itself seemed to be notably better than what I remembered. I am hoping that will also be the case with the 7×43 when the time comes next month.