I have a pentax mz5n, my first AF camera ok, it replaced my much loved Nikormat, with 3 prime lenses. I accepted the compromises -as ever- I travel, i wanted flexibility, speed of use and lightness, it could get broken or stolen.

I decided I wanted an AF with a zoom.

The mz5n has a 'pentax'28-200 3.8-5.6. I recently discovered it's tamron. dissapointing. It was all that was available where i was at the time that my Nikormat started having problems.

But its been slow to focus, and often doesn't, and picture quality is not good, esp at the hi end.

I am being told now that the camera is cool, but the lense is crapola hence the focus problems.

I get to travel a lot, I often get off the 'track', these are rare moments, I love my pictures, I want better ones.

I am considering the sigma EX series 24-70 and the EX 70-200 and maybe a converter. it seems that Sigma don't make the HSM for pentax.

I now suspect all lenses are much the same $ for $ so maybe the EX range are close to the better Nikons (????)

But, I'm within an ace of selling the MZ and going back to Nikon for the lenses. Or am I being naive in my faith in (the better) nikon lenses? I have had some lovely Nikon lenses, like that 1.2 50mm THAT I LOST! Damn

anybody got any opionions, or other sites regarding these lenses, or my camera.

I want to get this lense thing as right as possible, i'd like to go to a digital when a full chip slr becomes affordable so the lenses should have a long life for me.

I'd REALLY appreciate ANY information as otherwise I seem to have spend money to find out, and its bloody expensive.

A.

-- anna edgar (anna.edgar@lineone.net), February 11, 2002

Answers

"I am being told now that the camera is cool, but the lense is crapola hence the focus problems."

Okay. I/we agree. So what's your question?

-- Jim Strutz (j.strutz@gci.net), February 12, 2002.

Dear Jim, Thanks for answering, perhaps i tried to cover too much stuff. Er, what is it we are in agrement with ? That the lense is no good?

in essence my questions are: Is the problem I have been having due to the camera or the lense?

and assuming that its the lense, which I do

Do you have any comments on the two lenses I am proposing to replace the existing lense with the EX series 24-70 and the 70-200

A further query if I may be allowed is that having read someones comment about quality control being responsible for the hi price tag of some lenses, is this the case with the sigma?

I have found comment/review on the telephoto but nothing on the 24 - 70. It seems to be an unknown.

Dont know if you can help with any of this but would appreciate it if you could Thanks A

-- anna edgar (anna.edgar@lineone.net), February 12, 2002.

Actually the Pentax/Tamron 28-200 isn't bad for a 28-200mm lens, but that doesn't mean it's a good lens, just that it's better than some of the others in it's class. Most wide ranging zooms make quite a few optical compromises. The wider the range, the more the compromises. Also the lower the cost, the more the compromises. That's two strikes for this lens.

The Tamron 28-200 isn't all that sharp at the long end, it's aperture is slow and their are too many lens elements to be very contrasty. All of this combines to make AF more difficult. So the bottom line is, sure, a quality fast aperture lens will focus faster and more reliably.

The Sigma 28-70 f/2.8 was/is a very decent lens and a remarkable buy. The newer 24-70 f/2.8 is said to be be even better, but I've never used one. They are certainly not the best lenses in this range, but the for the price they are very good. The Sigma 70-200 f/2.8 is generally regarded even better.

The reason that their are no Sigma HSM lenses in the Pentax mount is that it's not possible without Pentax doing some major remodel work on the lens mount and enabeling this feature in their camera bodies. Minolta is in the same situation. Pentax doesn't seem to be doing much innovation these days however, so it probably won't happen soon, if ever.

-- Jim Strutz (j.strutz@gci.net), February 13, 2002.

Thank you Jim, this is very helpful. You say the sigma are not the best in this range. Out of curiousity so that I might do a price comparison which are 'better'? Thank you again A

-- anna edgar (anna.edgar@lineone.net), February 13, 2002.

Pentax's own 28-70 f/2.8 and 80-200 f/2.8 ED IF are certainly better. Probably the best in these ranges for Pentax cameras. The Tamron 28-105 f/2.8 and also the Tokina 28-70 f/2.8 are also regarded as better better, but I've not used those.

-- Jim Strutz (j.strutz@gci.net), February 13, 2002.

Anna, Just to add to Jim's good summary, I would imagine that when Jim talks about the Pentax 80-200 being better than the Sigma 70-200, he's talking about a fairly minor difference-I'm sure that if you viewed them side by side on anything other than a microscope you'd be hard pushed to tell the difference. As Jim says, the Sigma 70-200 has a good reputation, as did the older 70-210 which I have used. They also handle VERY nicely, and of course are cheaper than the Pentax. You may find the Pentax lenses are built slightly better, but again with independent lenses aimied at serious users like the Sigma EX's they also tend to be pretty good. I thoroughly agree with the Tamron comment too. Don't be tood hard on Tamron, the huge focal length range of these mega-zooms is the culprit. This is why Leica and Contax Carl Zeiss don't make them, as even they couldn't make 'em any good and they'd tarnish their reputations.

Best of luck, Steve

-- Steve Phillipps (steve@redvixen.freeserve.co.uk), February 13, 2002.

Thanks for this, both of you, I know what you mean about the 'mega' zoom lenses, when i first bought the camera i bought it with a pentax 28-105, that i think I mentioned, it fell to bits almost immediately.It was a Taiwan or chinese build, i cant remember. I then went to the 28-200 which is a japanese build, thinking it might be better, and having been out of touch with cameras for some years, just thought 'what the hell, they must have gotten this thing with the big inclusive compromises together by now'. Well, i realised there was going to be some compromise with picure quality, but didnt realise that it might restrict the working of the camera. SO, all in all i now feel that the compromise is too great. Like I said, I always liked using 24mm lenses, and I'd like to find out if that 24-70 is ok, or not. I have also been chasing some info on the pentax 24-90 and the tamron 24-135 , they seem to be a similar price. BUT is this inclusion of the 24mm focal range once again increasing the compromise unacceptably? Both of these are f/3.5 - 4.5 pentax, and 5.6 tamron respectively.Generally the faster 2.8 seems to indicate a better quality lense do you know anything about these two?. The only people making a 2.8 constant seem to be Sigma, in my 'most desired' focal range are Sigma. But opinion here seems to be divided. I found a mention of a review of the 24-70 F/2.8 EX in the oct 2001 shutterbug, but cant bring it up. This process has been really interesting as its made me really consider what i need for what i do, and at this point am thinking that while i need a fast AF zoom for the wider ranges 24/28-70/80/90, I will probabaly be happier with a couple of long primes for the upper range to 200mm, and these could be MF. Ther s no reason why they shouldnt be compatible with a full chip digital slr. when one of these finally happens affordably. I did hear that Pentax were working on it but the chip was worth 6K (G.B.POUNDS for gods sake!!!). Do you think it'll happen? Any guesses as to when, and how long before its an affordable item :-) sorry! A

-- anna edgar (anna.edgar@lineone.net), February 14, 2002.

Anna, For what it's worth, in my opinion you'd be better off with MF wide lenses and fast AF telephotos. This is because with wides focus is not so critical as there's more depth of field, while with teles it's very tricky to keep focus on fast moving action. As for the 24-70 Sigma, I had one briefly and was never really happy with it. I think your point is spot on-that the including 24mm in the range pushes the lens a bit much and results in poorer quality. Did you know that Sigma made a very impressive 24mm f1.8 lens that was very highly regarded? Might be worth a look.

Lots of luck

Steve

-- Steve Phillipps (steve@redvixen.freeserve.co.uk), February 14, 2002.