Should I get 77mm or 70mm?

We have a 3 lens set of the "limited" lenses coming to photo.net for a review sometime in the near future.

In terms of focal length, there isn't much practical difference between 70mm & 77mm. And from what I hear, they are both nice lenses, so get the one you can find and/or afford.

There is actually a 10mm difference, as the 70mm comes in at 67.6mm tested. As to focal length, try using your zoom experimentally at 70mm for a while, then at 80mm, and you will get a feel for the difference. The longer reach would be better for portrait use without getting in the face of subjects. Also better for candids, as people are less likely to notice their picture is being taken, when the shot is done from a greater distance.

The 70mm, like the 21mm and 40mm Limiteds, is the new DA design for digital cameras, has the new easier-clean coating, and the shift for manual over-ride of AF.

The 77mm still has an aperture ring, and can be used on all Pentax cameras, past and present. It also offers one more stop of speed with an aperture down to f/1.8, which is better for lower light and/or higher shutter speed.

Both are remarkably small considering their focal length and aperture.

Thanks for the information...still a tricky decision! And from what you have said, you think I should add one of those to my 50? And what about wide angle? I was thinking of a manual 28mm 3.5 or 2.8 on Ebay, are either of those any good?

I can only speek to a part of your question. The 77mm f1.8 has nice brokah; no idea of the other (70mm) lens.

In the 28mm world the 28mm f2.8 M and A are very light weight, (49mm filter) but are only reported to be 'decent' lenses. I have the M version, and I'm happy with it because it is so small and light weight and takes very decent photos. The f3.5 is said to be optically a better lens.

Erika -- I have a Kiron 28mm f/2 that is outstanding. They come up on ebay from time to time. It gets the most use on my *istDS, though. I prefer the 35mm 2.8 for my film camera wide-angle.

I have owned and used both the FA77 and DA70. The field of view difference is a bit larger than the nominal focal length differences might indicate (the DA70 seems to test out as slightly shorter than 70mm and the FA77 as slightly longer).

Aside from the obvious weight and size difference (the DA70 is half the length, 2/3 the weight), the DA70 focuses more swiftly and has the Quickshift focusing feature. It's not designed to cover 35mm film format. Rendering-wise, they are about as identical as two lenses can be that are of different focal lengths. The DA70 might have *marginally* less CA but by such a small fraction it's inconsequential. The FA77 has an aperture ring so can work on an old-style K-mount bellows or extension tube where the DA70 requires a KA- mount bellows or extension tube.

Both are excellent lenses. Pick the one that suits your fancy and enjoy it. I prefer the wider field of view of the DA70 and its QuickShift focusing feature, also its smaller slze.

Godfrey

As others like Godfrey have pointed out, both are good lenses. The DA70 "pancake" is smaller and I find that appealing as I generally prefer to travel light. Here are links to two sets of photos taken with the DA70, if you want to see a range of sample photos.

San Clemente Car Show

Amsterdam

Ned

I agree with Donnie: the Kiron 28mm f2.0 seems to perform as good as the Pentax A 28mm f2.8. OTOH I don't like using plain k-mount lenses without A setting on DSLRs. I also have trouble setting focus manually, especially in low light situations (I tried shooting concerts with a Exakta 24mm f2.8 lens), so I can only suggest to get some AF wide for indoors, since wides are harder to focus on SLRS in general and the DSLR screens are especially nasty. The Sigma 24mm f1.8 is a huge chunk of glass and plastic, but if you don't mind that, something to start with and maybe add a 14mm f2.8 Pentax later to a 2nd or 3rd body. Old Sigma 14mm f3.5 A lenses don't perform really well, so safing to get the Pentax is a good idea.

The Pentax 28mm f3.5 has a good reputation, but to me it seems more like a compact hiking lens than a indoor available light performer and it isn't really wide, so the 21mm limited lens might be a better choice, if size matters a lot.

Jochen -- I agree about the focusing. I got a split-image/microprism screen on ebay that works great. I just wonder why Pentax doesn't offer them --it makes manual focus a snap!

I just got the 77, and it really is a fantastic lens. The pancake 70 is appealing but I decided that if I were spending this much money on a new lens, I wanted to be able to use it on 35mm as well. I'm not sorry about this decision, and anyway the extra bit of speed doesn't hurt.

I have only two (minor) complaints about the 77. As others have said, the AF is on the slow side, at least in low light. It's fine outdoors, but in poor light it can take a moment to get focus confirmation, and the proportion of failed focus attempts is a fair bit higher than with the kit lens.

The other minor issue is the lens cap. It's a rather old-fashioned push-fit metal thing that looks nice but isn't especially convenient compared to more 'modern' clip-on ones.

Regardless of these criticisms, this really is an amazing lens. It's sharper wide open than the vast majority of other lenses are stopped down, but its rendering never appears harsh. It produces images with a remarkable 3D quality. I thought this might have been over-hyped before getting the lens, but it's not. I think this may be down to a particular combination of high resolution and super-smooth transitions between in focus and out of focus areas.

Oh, and I also shoot with a DL. I figured it made far more sense to go for good glass than to spend the same money on upgrading the body.

Matthew

I own the 77mm. I have to say it is a fabulous lens, and has produced my best work. My only issue with the lens is the auto-focusing. I used to use it on my *istDl, and found that it had a hard time finding focus (perhaps it was the subject matter, normally portraits). Then I bought the K10D, and it has the same problem, even with enhanced focusing features it is very slow to find focus.

There is a basic design reason, IMO, for the 77mm Limited being not as zippy in AF speed. I have noticed it, but not found it to be a problem in practice for me.

Its focus mechanism is designed closer to that of the old manual-focus lenses, which have greater rotation in their focussing range. This means slower AF, but better for precision fine-tuning of MF, and an exceptional MF "feel".

BTW, to each his own preference, but I like the push-on felt-lined metal cap. I find it classy, more protective, and less likely to accidently come off. As an alternative, a standard 49mm plastic clip-on cap will also fit. I sometimes use one of these on my 43mm Limited when I want to go without the lens hood for more compact carrying, but using one on the 77mm does not reduce its size.

As to 28mm: it is a good, convenient focal length, as a compact semi wide-angle on a DSLR. A useful view angle, allowing more in the frame than a 35mm view would, which no longer provides any wide angle viewing on a DSLR. I think a 28mm provides a more versatile standard view on a DSLR, before going into a tele-view focal length.

If you can find one, get the FA28mm f/2.8 AL- a very fine lens. Really tack sharp starting around f/4. Excellent contrast & color, and AF is often advantageous to achieve quicker focus, when objects in the viewfinder are rendered smaller by any wider-angle view.

One final thought- since you have the very fine FA50mm f/1.4, the longer 77mm Limited may be a more significant increase in reach for your needs in that direction. It is also possible to go longer yet in still a compact package by using it with a 1.4 teleconverter, giving you a 108mm f/2.4 lens with greater close-up magnification! Of course, you do lose some of the excellent quality by using a TC- but still should be very good.

For digital, I often take a compact trio like the 21mm and 77mm Limiteds, and the FA28mm for the middle. If I don't need the reach of the 77mm, I'll substitute the 43mm or FA50mm f/1.4, depending on the situation, and need for compactness. I may also pack along a tele zoom, if I think I may need it.

For film, it will generally be the FA28mm, the FA43mm and 77mm Limiteds, and maybe a tele zoom. When going less compact, I may opt for the Tokina 19-35mm ultra-wide zoom over the FA28mm.

I should have mentioned, especially for film, I will often prefer the FA35mm f/2 AL.