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Heads done in. ADVICE PLEASE! (1 Viewer)


Well-known member
Hi guys

Once again I would love to hear the thoughts and opinions on lenses for my Pentax K-x.

I am toying with the following.

The Prime DA* lens 300mm and the Sigma 150-500 lens that supports Pentax.

I really need help because its a lot of money and I want to make sure i get the best. Do I go for the prime and crop or get the Bigma?

I am prepared to sit it out in fields and rivers so I can justify either




Well-known member
Just to throw a spanner in the works, how about the Sigma 120-400mm?

No doubt the 300mm prime will give the best quality, but its not as versatile and probably more expensive too

I had two Pentax DSLR's, but went to Canon for the wider range of lenses, do wish Pentax would make something longer because really like their cameras and the K-5 looks and sounds great.


Well-known member
It certainly is a bit of a difficult decision. Over time though I bought both! ;)

The DA*300mm is certainly a superb lens and I use it wherever I can, but the longer reach of the Sigma is certainly very useful in a lot of situations. I guess it depends on the subjects and how close you can get to them a lot of the time.

The Sigma, whilst long and heavy is certainly useful handheld and I can walk around all day with it on a sling attached to the ample tripod foot.
The DA*300mm is often with me though, even if I have the Sigma attached, for larger insects - Butterflies, Dragonflies etc - as this is where it really shines.

I think there really is no hard answer but if you are thinking primarily of birds, I'd go for the Sigma and the longer reach.

Of course, if Pentax gor their act together and brought out the long rumoured 1.4x TC, the DA*300mm would be a no-brainer!
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Well-known member
I have both lenses for image quality the 300 prime wins hands down, but as prevoiusly stated the the extra length of the siggy is great for long distance bird shots, if had to choose i'd go for the 300


Well-known member
Hi Alistair,
As I think I previously mentioned I had the Bigma 50-500mm for a while before I purchased the DA* 300mm and the lens hardly came off the camera, just loved it. Bearing in mind most of my photography is wildlife.
Difficult choice Alistair, but for my needs the DA* 300mm wins.
Luckily I have the Pentax 18-55mm, Pentax DFA 100mm Macro, Pentax DA* 60-250mm,
Pentax DA* 300mm and Pentax FA* 600mm so I am well covered.


Well-known member
Well covered? Well endowed as well!

Thanks for all that feedback guys. The beauty of the DA* 300 and its cropping value might just be the way to go.

Whats the 120-400 like Huntso?

Thank you all



Well-known member
The 120-400 from what iv'e heard and read is supposed to be a bit sharper than the larger lens and obviously lighter too.

As mentioned I now use Canon and was set on buying this lens myself, only changed my mind when the family kindly bought me a 400mm prime for Christmas and Birthday.


Well-known member
I think we worry too much about IQ, the DA*300mm will hold its own against anything you throw at it but the Sigmas are quite capable bits of glass, I think my PPG gallery proves that.

My advice would be to go for the Zoom, it will be far more versatile, you can always save up for the 300mm later.

As for bemoaning the fact that Pentax don't produce long enough lenses I doubt that 90% of us would be able to afford then anyway, the last price I can recal for the FA*600mm was something like £6000|8.|


Well-known member
Can I assume folks that the Bigma 50-500mm will fit onto the k-x ok?

The guys that have used the Bigma (tom eg) whats your experience with using it handheld and stupid question. Do you stick this thing on a monopod/tripod and snap as usual? Isnt it better using a remote or something?



Well-known member
Long Barrel

The Bigma was always good, and now with OS it is said it is quite sharp. However on a pod it will perform best.

having said that the DA* 300mm from pentax is such a brilliant piece of work that, i doubt you will miss the reach. It will allow very good cropping on the Kx and even better on the K5.


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