A Work Commenced January 27 2024
Product: Celestron Granite 7 x 33
Country of Origin: China
Chassis: Rubber armoured magnesium alloy
Exit Pupil: 4.71mm
Eye Relief: 15mm
Field of View: 159m@1000m( 9.1 angular degrees)
Close Focus: 2m advertised, 1.64m measured
Coatings: Fully Multicoated, phase corrected Schmidt Pechan roof prisms
ED Glass: Yes
Waterproof: Yes
Nitrogen Purged: Yes
Weight: 601g
Status: Discontinued
Over the years I’ve reviewed a number of Celestron binoculars and have been impressed by their efforts to bring higher than average quality optics and ergonomics to the market at prices that are affordable to many, such as the Trailseeker line and the more advanced Regal ED, for example, being the most recent examples to come to market. However Celestron actually began their foray into advanced roof prism binoculars about 12 years ago, when they launched their sophisticated Granite series, featuring an open bridge design, ED glass, fully multicoated and phase corrected optics. Initially, the series included 8 and 10 x 42 and larger, 10 and 12 x 50 models. But the general success of these instruments led to the marketing of a further two smaller models:7 and 9 x 33 Granites.
In my new book, I showcased a mini review of the 7 x 33 contributed by Philip Grimsey, a keen birder and amateur astronomer, based in Hitchin, England. My first encounter with Phil came through a purchase of a classic Russian 7 x 35 binocular, which turned out to be a very pleasant surprise and since then I’ve discovered that Phil is a kindred spirit, having a very similar taste in optics to yours truly.
Phil contacted me asking if I’d like to test drive the 7 x 33 Granite for myself. Curiosity got the better of me and I accepted his kind offer.
Ergonomics
My first impressions of the instrument were very favourable indeed. The magnesium alloy chassis is overlaid by a thick layer of matte black rubber, which affords excellent protection from the elements as well as accidental knocks and bumps. In addition, the underside of the instrument has shallow grooves for resting your thumbs in while glassing. The Granite was one of the earliest econo models featuring an open bridge design for superior handling.
Tipping the scales at just over 600g, the Granite is nifty, light-weight binocular that can be taken pretty much anywhere.
The nicely machined metal eyecups are overlaid with soft black rubber. They are very firm, with one intermediate position between fully retracted and fully extended, locking rigidly in place in all configurations. I think they’re excellent: a little smaller than the larger frame of Celestron’s more recent models, but right up there with those I’ve seen on models costing much more. Eye relief is very generous too: I was easily able to engage with the entire field wearing my eyeglasses.
The large, centrally placed metal focus wheel is overlaid with raised strips of rubber which greatly assist with its turning. I would describe this focuser as being on the fast side, taking a little over one revolution to go from closest focus to a little beyond infinity.
The dioptre compensation wheel is quite sensibly placed under the right ocular. It’s good and tight and held its position very well.
The Celestron Granite 7 x 33 has very nicely applied antireflection coatings which present a fetching bluish bloom as seen in broad daylight. Clearly they’ve held up very well over the years since its manufacture.
In the hands the little Granite 7 x 33 feels great, with plenty of room to position one’s hands to get an optimal grip. I had one minor niggle with the central hinge though. I felt it was a little loose for my tastes but in practice it never presented a problem.
I did like the ocular covers though, which are tethered via a bracket on the underside of the barrels. They snap into place to seal off the objective lenses from dust and moisture.
Optics
I checked to see how the Celestron Granite handled an intensely bright beam of light. It did very well indeed. Internal reflections were very well subdued and while I did detect a small diffraction spike around the light source but it amounted to little or nothing when I turned it on a bright sodium street lamp after dark and also on a bright gibbous Moon.
Examining the exit pupils also showed good results with only a fairly inconspicuous light leak around the main pupil(see below):
The view through the Granite is very good: it has excellent central sharpness with some peripheral softening as the field stops are approached. The large smooth focuser makes dialling in the precise focal plane easy. There is also a modest amount of pincushion distortion in the outer field. And boy what an expansive field it possesses at 9.1 angular degrees! I would describe the colour tone of this instrument as distinctly warm. Colour correction is excellent: there’s effectively none within the sweet spot and I could only detect a trace in the outer portion of the field while glassing through denuded winter tree branches against a bright overcast sky.
As you’d expect from a 7 x wide angle glass like this, depth of field is very generous, being noticeably deeper than 8x or 10 x instruments, thereby requiring less frequent focusing. Close focus distance was measured to be just 1.64 metres: an excellent result and well below the advertised 2m.
Having readily enjoyed a 7 x 35 Porro prism binocular for quite some time, I’ve come to appreciate the sheer comfort of a larger exit pupil with an expansive field of view. The Granite served up a field quite reminiscent of the Porro but with a flatter, less 3-dimensional view.
I was able to ascertain more about the aberrations in the outer field by testing the unit under the stars. Stars remained tiny pinpoints of light within the sweet spot, which extends to about 60 per cent out from the centre, after which the same stars began to slowly morph and bloat as the field edges are approached. A lot of this could be focused out, indicating that field curvature was the main contributor, but some coma and astigmatism was also clearly present right at the field stops. Examining a bright gibbous Moon as it was panned from the centre to the field edges showed much the same thing.
Glare suppression is very good in the Celestron Granite 7 x 33 too, performing well against the light but also handling veiling glare very effectively.
In Praise of the 7 x 33/35mm Format
In chapter 30 of my new book, I discussed some very charming 7 x 35 instruments from yesteryear, including a number of classic Porro prism binoculars such as the Nikon Action Mark I with its excellently corrected 9.3 degree field, the Swift Holiday Mark II with its 11 degree field, and the Sans & Streiffe sporting a whopping 13 degree portal on the world. But companies like Leica (formerly Leitz)also marketed iconic roof prism models such as the Trinovid 7 x 35B manufactured from the 1960s through the 1980s and recently revamped in the ornate 7×35 ‘Retrovid’ with its upgraded coatings.
The Celestron Granite 7 x 33 was the first Chinese manufactured instrument to break the European and Japanese monopoly on these instruments and did a rather excellent job to boot. Sadly the Granite 7x 33 was rather quickly abandoned for reasons unknown to this author but I hope this article will encourage other manufacturers to take up the gauntlet to produce a new 7 x 35 at prices that won’t break the bank. The advantages of such an instrument include:
Small. lightweight and portable
A wide and stable viewing experience
Improved depth of field over higher power models
A large exit pupil for improved performance in low light.
Such instruments are likely to prove very popular with birders, and outdoor enthusiasts and even for doing some casual astronomical viewing. It would be remiss of me not to also mention the Hawke Endurance ED Marine 7 x 32 with its 8.3 degree field, although this particular model was created for marine use. Will we see a model like the 7 x 33 Celestron Granite making its reappearance in the market? Time will only tell!
My thanks to Philip Grimsey for lending me the Celestron Granite 7 x 33.
Thanks for reading
You can read a great deal more about hundreds of other contemporary and classic models in my new book, Choosing & Using Binoculars: a Guide for Stargazers, Birders and Outdoor Enthusiasts.