A Work Commenced July 8 2021
Product: Zeiss Terra ED 10 x 25 (TL Edition)
Country of Manufacture: China
Field of View: 97m@1000m/ 5.4 angular degrees
Eye relief: 16mm
Close focus: 1.9m
Exit Pupil: 2.5mm
Chassis material: fibre glass reinforced polyamide
Coatings: Zeiss T*, lotutec, hydrophobic coatings on outer lenses
Dioptre range: +/- 3 dioptres
Nitrogen Purged: Yes
Waterproof: Yes to 1m( unspecified time)
ED Glass: Yes (Schott ED)
Dimensions: H/W 11.1 x 11.5 cm
Warranty: 2 years
Retail Price: £300 UK
Supplied with: soft storage pouch, carrying strap, lens cleaning cloth, multiple language instruction sheet
In a previous review blog, I bought in and tested a Zeiss Terra ED 8 x 25 pocket glass. There I reported its excellent performance and very good value for money given its Japanese optics and congratulated the company for bringing to market such a wonderful product that would would allow many ordinary people on a strict budget to sample real optical quality. But it was also a time of transition, as all of the other Terra models had shifted production to China and some controversy arose as to where the more recent Terra pocket models were being manufactured, and some folk began to chime in stating that their Terra pocket glasses were now being made in China.
In this communication, I wish to discuss a brand new Terra pocket glass with a 10 x 25 specification, clearly marked as made in China on the box and on the underside of the chassis. The ‘ED’ in the name is replaced by ‘TL’ which I am led to believe is short for ‘Travel.’ That said, the ED specification was clearly stated on the outside of the box. I’ve already covered much of the background to this product in the 8 x 25 review. Here I wish to give the reader my opinions on its optical performance and whether or not I think it is worth the fairly substantial price tag.
As you can see from the picture above, the newly presented Terra ED 10 x 25 is not the same as what I received with the 8 x 25 model. The box is a lot smaller and of much lower quality than the lovely, large hardboard box I received in the Japanese made 8 x 25 model. Also missing was the arresting alpine vista on the inside of the presentation box. All in all, it was poorly fabricated in comparison. Gone too was the good quality hard clamshell case with magnetic locking latch. Instead, I received a flimsy soft pouch which offers no protection of the binocular apart from keeping some dust out. Ho hum. The carry strap and lens cleaning cloth were the same however, which is something.
The design of the chassis looks identical to the 8 x 25 and feels good in the hand, but I was surprised to see quite a bit of dust on the objective lenses, not like the immaculate presentation of the 8 x 25. That was quite surprising, as I had come to expect better from Zeiss. But what shocked me most was the optics.
I began with my usual iphone torch test, a simple but very discriminating exercise that reveals internal reflections, diffraction spikes and diffused areas indicative of how homogeneous the optical glass was. It involves directing a very bright beam of light into the binocular and studying the resulting image visually. I’m relieved to say that it did pass this test with flying colours. Consulting my old notes I made on the 8 x 25, the 10 x 25 offered up pretty much the same high quality results, namely, a clean image with a couple of very subdued internal reflections, no areas of diffused light and a weak diffraction spike. So far so good.
After adjusting the dioptre setting for my eyesight, which is accessed at the end of the bridge, I took it outside in bright daylight to gain a first impression of its optical performance. Like the 8 x 25, the 10x model offered up a bright image(it has an advertised light transmission of 88 per cent) but it was a lot more difficult to focus well owing to a very stiff central focus wheel. Maybe I had been spoiled by the buttery smooth focuser on my beloved Leica Ultravid 8 x 20. Whatever it was, I was not impressed by its resistance to turning. I do not recall having an issue like this with the 8 x 25, as my notes reminded me.
The image itself was good but not great. Much of the quality of the 8 x 25 was there, bright and quite sharp across much of the 5.4 degree field. Contrast was very good and it was quite resistant to glare when I pointed it near a brightly backlit tree. But I was shocked to see that the image had a lot of chromatic aberration, both in the centre and especially off axis. Indeed, it had more chromatic aberration than I had ever encountered in a binocular of this specification – and I’ve tested quite a few models in this regard. My target was a Conker tree in full Summer foliage backlit by a uniformly bright overcast sky and my eyes were drawn to the blue fringing of the leaves which was very strong off axis but also present more weakly at the centre of the image.
In comparison, the little Leica 8x 20 Ultravid showed none, or rather the merest trace at the extreme edges of the field, and only if I deliberately looked hard for it. Truth be told, I was left totally underwhelmed as I had expected much more from the Schott ED element at the heart of this £300 Zeiss designed binocular. What is especially ironic is that the Leica Ultravid 8x 20 doesn’t have an ED element yet delivered a much higher quality image in this regard. I don’t think it was an optical flaw as the image was otherwise quite sharp to the eye. In a previous correspondence, I noted that the Leica Trinovid HD 8 x 32, which also has an ED objective element, also showed some chromatic aberration in similar tests but nowhere near as much as this 10 x 25 Terra pocket.
In another test on a telephone pole located some 30 yards away and also backlit by a bright overcast sky, I compared and contrasted the images of the 10 x 25 Terra with my Barr & Stroud Series 5 8 x 42. Again the result was the same. The non ED 8 x 42 showed far less chromatic aberration at the edges of the pole compared with the 10 x 25 Terra, and while lateral colour increased as I moved the pole to the edge of the field in both binoculars, it was far more pronounced in the smaller 10 x 25 Zeiss glass.
These tests showed me that having an ED glass element is no guarantee of better colour correction, as both my 8 x 42 and 8 x 20 clearly showed.
I also bought in the 10 x 25 Zeiss to test image stability compared with my 8 x 20 Leica Ultravid. Again, I got on far better with the latter glass. The 10x magnification in a small frame made getting a steady image very challenging in comparison to the much more stable image of the little Leica glass. That test convinced me that I will be sticking with 8 x 20 format for the foreseeable future.
The experience with the Chinese made Zeiss Terra ED 10 x 25 was not at all what I expected. It was much inferior to the views of my original Japanese made 8 x 25. The focus wheel was far too stiff and the colour correction was just not acceptable. I returned the instrument to the seller and received a full refund in return. Nothing ventured, nothing gained!
Not recommended for its considerable retail price!
Dr Neil English has over 40 years experience studying the night sky with all sorts of telescopes, but in the last few years has devoted himself to seeking out bargains for savvy binocular enthusiasts. His highly lauded 650+ page magnum opus, Chronicling the Golden Age of Astronomy, summarises four centuries of telescopic observing, from Thomas Harriot to Patrick Moore.