Sunday, July 22, 2012

Bushnell 28mm Lens Review

One of the nicest photography spots in my home town is the Campus of Mt. Allison University. Like most campuses, it is replete with beautiful architecture, and Mt-A has been exceptionally good over the years at maintaining its older buildings, and when new buildings are added, they continue with the well established theme. I went out this morning with a dual purpose in mind, to once again photograph some  of this beauty, made even more serene by the lack of activity in the summer months, and also to give my 28mm f2.8 manual focus Bushnell lens a thorough evaluation.

Here are the few pictures that I took on the Campus, and along York Street.

As for the Bushnell Lens, it seems to be very rare and I cannot find out much about it. Bushnell of course is famous for its Binoculars and Rifle Scopes, and they did make a brief entry into camera lenses in the 1970's, although I cannot find any info on the Web for dating mine. It is an M42 Pentax Thread Mount type, as are all of my manual lenses, which by default puts it in the late '60's through mid '70's. It is extremely well made - perfect, really, with a satin black aluminium finish and rubber grip with no plastic parts at all - even the end caps are machined aluminium. My assumption is that it is of Japanese manufacture, simply because the Koreans and other Asian countries were not making lenses during the M42 era. Like I said, this lens is mechanically and aesthetically perfect, and also fairly large in size, with a 58mm Filter Thread (same size as Canon's Kit Lenses). I also own a Bushnell 90-230mm f4.5 M42 Zoom, which is absolutely "stupid huge". It's heavy enough that it has it's own tripod mount, and in terms of build quality, every bit as excellent as my 28mm.

Just to review how I manage to use lenses like this on my DSLR, for you new-bees. Since the advent of Digital SLR cameras, there has been an explosion in the manufacture of lens adapters. You can pretty much adapt lenses of any brand and type, from any interchangeable lens camera made since the 1930's, to any new DSLR. For some combinations, these adapters have to include one optical "helper element" to ensure focus-ability to infinity, and this is best avoided if you can, but as a Canon owner, old lenses that were made with M42 and the newer Pentax K-Mount work perfectly with non-optical adapters. However, older Canon "FD" type lenses, such as was used on the famous Canon AE-1 will not work with the newer Canon EOS mount without the extra optical element being included. I had tried this a couple of years ago, and was never happy with the results. So it can be done, but some combos work much better than others.

One other cool feature is that most of these adapters have a built in electronic chip that mates up with your DSLR body contacts. This allows two things to be enabled on a DSLR that goes beyond the capabilities which these old lenses were designed for, and how cool is that!! The first is that Aperture Priority mode can be used, and the second is that, although you have to focus the lens manually, your camera body still uses it's phase-detect focusing, and will give you the "beep" signal when focus is achieved - in other words you get an audible focus assist! There are a few proviso's to keep in mind to make this work properly:

  •  Make sure your focus alert audible beep is turned on (via a camera menu item)
  • The focus detect that makes it beep requires a lot of light to operate, so if your older lens aperture is stopped down any more than say, f5.6, there won't be quite enough light coming through for the focus phase detect to get a reading. If you need to stop down more than f5.6, then what you need to remember to do is go wide open, then focus until you hear the beep, then stop down to you desired aperture. 
  • These chips on the adapter will only allow your camera body internal aperture setting to go to f1.4 - no lower. This means that your actual exposure is affected by about 1-1/2 to 2 stops, so to get correct Aperture Priority exposure, you need to set your Exposure Compensation for up to 2 stops under-exposure. 
Once you get used to these things with a little practice and experimentation, you might find a real preference to using old manual focus lenses. You can clearly see what's in and out of focus in the viewfinder, and with the chipped adapter, you get the audible focus confirmation. 

Back to the Bushnell 28mm. I found it to be a rather soft lens, when compared with an old M42 Takumar especially, or even compared with the Canon EOS kit zoom, which is very cheap, but sharp. If you don't mind slight softness, it's not a bad lens. I also found that it gives a very slight greenish cast to some photos. Bottom line - you can easily compensate for both the softness and colour error in Post Processing (assuming you're shooting RAW), but unless you insist on using the Bushnell 28mm (assuming you can even find one), because of it's amazingly great build quality and smooth action, there are much better optical qualities to be had with genuine Pentax Takumar, early (pre-Korean) Vivitars or even most of the Russian or East German M42's

1 comment:

  1. I inherited several Bushnell lenses from my late Grandfather including the 28mm, 135mm and 90-230mm and I agree on the Build quality aspect they are exceptionally well made even in the later FD mountings for a Cannon AE-1. They're heavy as well but not too heavy and can be finicky to use as you approach their lower F-stop values to the point where I would strongly recommend avoiding these settings whenever possible. (images may turn out too soft).

    I'm experimenting with an adapter made by Fotodiox to use them on a newer DSLR, despite the optical assist it does seem to be working quite well but its too early to say for sure.


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