[cyberjunkie]

I shoot mainly primes, often MF, but i realized that for travel photography a long zoom with decent AF would be very useful.
I don't know much about Sigma discontinued long zooms, but i know of at least 4 different optics, available on the second-hand market, that are full frame compatible and were made in Pentax mount.
I know that the last version of the 50-500mm "Bigma" is still sold new. It has a wonderful zoom range and a more than decent image quality, according to the experiences of many forum users, but it's out of my price range and very big.
I think that many owners of the new K-1 would be interested on the same subject, so i encourage the fellow pentaxian with specific first-hand experience to post their impressions/advices.

These are the models i've seen on sale, feel free to integrate the list:

150-500mm
170-500mm
120-400mm
135-400mm

I'm mainly interested in image quality and autofocus responsiveness with the K-1, though i guess that size/weight could also be relevant.

I'm sure the informations provided will be useful to many K-1 novices
Thanks

Cheers
Paolo

[svassh]

I have the 120-400mm Sigma that I bought off Ebay for a pretty reasonable price I think ~$450. Works well in FF has HSM focus motor and OS. I've only taken it out once and it performed well both in FF and APS-C with C-AF and 3x3 focus zone. Fairly quick to focus and able to track the ducks and my dog which is all I've shot so far. At f/8 IQ is decent, not great wide open but at this price point it punches above its weight.

Sample photos in this thread : Crop Mode Question - PentaxForums.com

[Cardinal15]

I too thought the Bigma (50-500) was out of my price range but I found one here on the market place and bought it for a very reasonable price. It was the first generation but as usual with lenses of this type its been very well cared for. It performs wonderfully and has proven to be very versatile. I have n't used it with a K1 (yet) but on my K3 the images across the board have exceeded my expectations. You're correct in that it's biggest negative is the size and weight but a friend of mind owns the 150-500 and the differences seemed minimal, the extra reach certainly offsets that. Also with a conventional neck strap this would be a burden to carry but I switched to a Rapid style sling strap and it is very easy to use and carry and not a burden at all. As with any of these super zoom lenses it takes a bit of getting used to and a learning curve to get great pictures but once you do you should be pleased.I recommend using a mono pod when convenient, it can help I highly recommend the Bigma and enjoyed using the 150-500 as well. The AF on both was fast and accurate it will hunt a bit in difficult lighting situations but I find that rare.Once you own one your perspective will change.Prior to the Bigma I used the Pentax A 400mm prime, which creates beautiful shots, for my long work ( I like birding and such) but since I got the Bigma I've found its versatility far more useful. I hope this gives some insight from a regular user.

[HarisF1]

How many versions of the Bigma were made?

I've just bought one from a pawnbroker/second hand shop that came fairly cheaply. It's a 50-500mm DG HSM from what I can see, but it doesn't look like an OS version. There are only two versions listed on the PF review site and this looks like neither of them.

[lesmore49]

I've had a Sigma 150-500 I've used for a few years. I use it to shoot wildlife, primarily birds and drag racing cars in action as they race down the strip. I've been very impressed with it's picture making quality. Pictures are sharp, clear, crisp. I use my K-5 body with it.

Before I bought it, I read both Canon and Pentax forums to get a 'feel' for how good this lens was. I found that people seemed to either like it, or not be too impressed with it. My feeling is that a lot of people that are not happy with the Sigma 150-500 are not setting it up/supporting it appropriately.


My suggestions:

This is a large, very long, heavy lens and you need to use it bearing in mind that one has to be careful with settings.

My hints for success with this lens. It's a bit on the slow side, I generally use it in bright, sunny daytime.. Light coloured clouds also work ok. I use 800-1600 ISO to get my shutter speed up above at the very least...1/1000th of a second. Remember the old focal length/shutter speed maxim....match the shutter speed with the focal length...ie;...300mm....at least 1/300th of a second. With today's easily set ISO...I try for at least 1/1000th...or better with this lens. The higher the better and oftentimes I using 1/2000th and faster. I use aperture control on the K-5.

The sweet spot for clarity in pix seems to be around F 10...F 11. I use these. I also use the Pentax Shake Reduction...I shut off the Sigma SR.

I also make sure I hold camera and lens...solidly. I don't use my tripod...I brace and support the camera/lens...very carefully. Practice, practice, practice. Go to a bird feeder with small, fast moving birds. Practice panning the birds, etc. I do this exercise for practice and to keep my skills up.

If you follow these procedures you should be off to the races.

I'm not a fan of taking pix of small birds though, mostly I try for the larger ones..Pelicans,Eagles, Owls...when I can find them. Again as mentioned previously, I try to hone my skills with small, fast moving birds.

[cali92rs]

I had the Sigma 100-300mm f4. It was a pretty awesome lens, but relatively hard to find. It is also by no means small.

[MoiVous]

I had the Sigma 100-300mm f4. It was a pretty awesome lens, but relatively hard to find. It is also by no means small.

I can second the Sigma 100-300 f4 - and yes it wasn't cheap. Handles and balances well on the K-1. AF is fast for a screw drive too - better than on my K5

Here are a couple of images from it with my K-1 taken a couple of weeks ago at Chinese New Year



(see this Flickr album for more Chinese New Year 2017 | Flickr)

I've also got the Sigma 120-400mm. That works reasonably well too, but I think the Sigma 100-300 balances better.