[jatrax]

The April 22 article is open for reading on the Pentax K-1 Special Site

Challengers | PENTAX K-1 Special site | RICOH IMAGING

Talks about the development of the DFA series of lenses

[northcoastgreg]

Article provides some hints as to why the DFA* 70-200 is so large and heavy:

“To minimize the level of vignetting at the edges of the image, a D FA-series lens must be designed considerably larger that its DA-series counterpart, because the incoming light must reach every corner of the larger image sensor,” the optics designer says.

There are also some passages that may explain why the 70-200 was delayed. They may have needed to rework the entire assembly line to solve a specific problem with the type of high-end glass they were using.

[UncleVanya]

Article provides some hints as to why the DFA* 70-200 is so large and heavy:



There are also some passages that may explain why the 70-200 was delayed. They may have needed to rework the entire assembly line to solve a specific problem with the type of high-end glass they were using.

That doesn't really clarify why it is so much bigger and heavier than the competing lenses for other systems to me. Unless it is due to IBIS vs. OIS. If that's the case Pentax may have to rethink how they approach this. Panasonic has recently started adding IBIS and combining OIS and IBIS in the newest bodies. I'm not clear how well this is functioning but if the lenses are forced to be larger than the competitors' products and not that much cheaper OIS may need to be explored for the telephotos just to keep down the size.

In any case there is room for that to come in the future should it be required.

[Kunzite]

It's not that much bigger - compared with the current 70-200mm lenses, it's not the longest (but registration distances will influence the lengths), and it's diameter is only 6mm larger than the smallest comparable lens (the Tamron), and 3mm than the largest (the Canon).
The difference is in weight.
Side by Side Comparison: Digital Photography Review

[UncleVanya]

It's not that much bigger - compared with the current 70-200mm lenses, it's not the longest (but registration distances will influence the lengths), and it's diameter is only 6mm larger than the smallest comparable lens (the Tamron), and 3mm than the largest (the Canon).
The difference is in weight.
Side by Side Comparison: Digital Photography Review

Good points - I really was thinking weight so I have edited my original to reflect that.

[Dave L]

I like this bit, it sounds like the Pentax we all know and love:

"Although it does offer the high-grade Star series of lenses, some PENTAX enthusiasts claim that the Star series models are the best lenses available, while others insist that the Limited series lenses are more perfectly designed for picture-taking."

[biz-engineer]

"Although it does offer the high-grade Star series of lenses, some PENTAX enthusiasts claim that the Star series models are the best lenses available, while others insist that the Limited series lenses are more perfectly designed for picture-taking."

That's poetry.

[Snappertim]

IBIS is the future, if Panasonis are working both systems then I suspect OIS is on the way out, IBIS is better at its basic function and the added bonus' of AA filter, shift lens, High Pixel, and Dust removal are just to good to ignore and as this becomes apparent to Nikon/Canon users the temptation to go IBIS will be irisitable, lets not forget Nikon/Canon started OIS in the film era and setled on OIS because IBIS was out of the question in a film camera, as any flexing of the film would have lead to striations and destruction of the negative surface, Pentax and Olympus and Sony all broke lucky by being late in, and during the digital era, IBIS works on all lens' and if a lens is designed for IBIS the size can be reduced.

[Simen1]

That doesn't really clarify why it is so much bigger and heavier than the competing lenses for other systems to me. Unless it is due to IBIS vs. OIS

Actually both approaches needs a larger image circle then a non stabilized system. IBIS because the image sensor moves within a larger stationary (with reference to the camera body) image circle. OIS because the image circle moves on the stationary sensor.

I don’t think the stabilisation group (glass, coils, springs) has to be notably larger or heavier then a stationary group, so in theory OIS shouldn't add much weight compared to IBIS. I don’t know the reason for the D-FA* 70-200 are heavier then the competition, but I suspect its due to extremely high optical quality. Something that should make this lens last (in sale) for at least a decade, even if we get 100 Mp FF sensors by then. If this is as I suspect, its similar to how Sigma have been thinking lately. Quality before lightweight.

[indy]

Lots of poetry...er ah... marketing speak. Some really good spin control re those that will inevitably complain about the preformance of older glass. I am really looking forward to disassembly and sample variation assessments from the Lens Rentals crew.

I love all of my Pentax glass and I would bet that they have knocked it out of the park with their in-house D-FA glass.

Ultimately they want to bring new folks to the Pentax brand, and what better way to do it than to offer categories of lenses that appeal to both the pixel peepers and the pixie dust crowds.

[MadMathMind]

I don’t think the stabilisation group (glass, coils, springs) has to be notably larger or heavier then a stationary group, so in theory OIS shouldn't add much weight compared to IBIS.

The Canon 70-200 f/4:
no IS: 705g
IS: 760g

The f/2.8 version with IS is 190g heavier than its non-IS counterpart. But the IS lens was resigned so the extra weight have a lot more to do with optical or other changes.

[Winder]

"The PENTAX lens designers put all their expertise and passion into the development of every single lens.".... Except the ones that they buy from Tamron....

[Zygonyx]

This doesn't negate the fact that lens designers may have been former pentax employees and may be working in another company... producing Pentax branded lenses...

[monochrome]

This doesn't negate the fact that lens designers may have been former pentax employees and may be working in another company... producing Pentax branded lenses...

Oh, Snap.

[Winder]

This doesn't negate the fact that lens designers may have been former pentax employees and may be working in another company... producing Pentax branded lenses...

Maybe. Maybe not. I don't have any problem with the Tamron zooms. I will be buying the 15-30mm very soon. The point is Ricoh really doesn't have as much control as they imply in the article when they re-badge 3rd party glass. Hopefully we see a D-FA* 24-70mm in a couple of years as Ricoh brings more lenses in-house.