July 27, 2022


Sony and Minolta SLR Weblog

Full-frame Sony DSLR? That big pentaprism is the clue

Big pentaprism tip off to a full frame Sony DSLRLike everybody else, I was tremendously excited to see the new prototype Sony DSLRs shown at the recent PMA show. Sony isn’t giving much in the way of details — all they have said is one of the cameras will be aimed at advanced amaturers and will offer features not available in the current A100. The other, of course, is aimed at the Professional market.

This answers the question that everyone wondered about when Sony first announced they were entering the DSLR market. They won’t be content to just cater to weekend shooters. They appear ready to take the battle directly to Nikon and Canon pro models. Bring it on!

What about that wild looking pentaprism?

The prototype of the unnamed professional model features a very distinctive pentaprism that sets it apart from any other DSLR on the market. When Sony uses the slogan “like no other” it looks like they mean it!

That strange looking prism might just be a major clue as to Sony’s plans for the pro model.

That pentaprism can only indicate a very high quality optical glass focusing system. Now, lets consider the implications of that.

Mirror and ground glass versus a EVF

While most photographers (including myself) prefer the superior focusing capability of a ground-glass and mirror system, there are a lot of very vocal proponents of the Electronic View Finder. They want to do away with the whole mirror and ground glass system and replace it with an EVF. Why keep all that legacy film camera claptrap – just put an EVF in and be done with it. I don’t like that idea very much – from my perspective, the ground glass system on even the cheapest SLR I’ve ever used is far, far superior to any EVF I’ve looked through.

Now the EVF hopefuls concede that the ground glass on a 35mm film SLR is superior to most EVFs. How could they not? The difference is unmistakable. But, they fire back, most digital SLRs use a small APS type C sensor. Because the sensor and the mirror size have to be matched in size, they argue that the smaller mirror doesn’t really provide much improvement over an EVF. The image is just too small to focus on fine details.

You probably can see where I’m going with this.

(1): Sony has apparently gone to a lot of trouble to design their new Pro model around a high quality optical glass prism.

(2): APS-C sensors (like those used in the Sony Alpha A100 and all current Nikon DSLRs) are too small to provide the focusing ability of a full frame 35mm SLR.

(3): The only details Sony has provided about the new pro DSLR is that it will have an all new sensor that Sony is designing expressly for the new camera.

It all adds up…

OK, add it all up and see if you math doesn’t indicate that the new top of the line Sony will feature a full frame sensor. Why design an expensive, intricate focusing system if you only going to be looking at a tiny ASP-C size mirror? It doesn’t make much sense.

Want more evidence? Sony has yet to offer any new lenses designed expressly for the APS-C sensor. Nikon and Canon offer smaller, lighter lenses designed expressly for the APS-C sensors, as well as larger glass that can cover the bigger full-frame sensors and 35mm film. True, most of Sony’s lens line has descended from Minolta’s film SLR lens catalog. They have announced some of their own lenses, however. AFAIK, all of them are full-frame lenses.

Of course the Sony DSLRs shown at the PMA show were merely concepts ñ they are not the final shipping product. Much could change before they finally are available for purchase. But Sony has indicated they intend to manufacture both cameras ñ that just won’t say when. It appears that one of them might ship this year ñ but the other will probably wait until 2008.

That’s timetable is fine with me. While I would love to get my hands a full frame Sony DSLR, today, I would rather that Sony take their time and get everything right, instead of shipping a camera with flaws.

In the meantime, we can all start saving our pennies!