[pearsaab]

I have the bigma os hsm, the da300 and the da60-250. I also have the pentax 1.7 adapter and have owned the tamron 1.4 teleconverter. I have also owned the f300 4.5...i love birds and that is what i use my long range lens for...here's my 2 cents

f300 4.5 extremely light (feels like a toy compared to the da), beautiful detail and bokeh, slow to focus. i loved this lens but the slow focus frustrated me so i sold it.

da60-250 another wonderful lens and has it's purpose for general use but would never use it for birds. not long enough. also tried it with the tamron 1.4 but didn't blow me away so sold the tamron

da300 i love this lens. not too heavy and easy to carry around. Detail, color and bokeh excellent. i have also used it with the tamron and pentax adapter. the adapter worked for me and i still use the combo when i don't want to carry the bigma. the pictures with the combo still have the wonderful bokeh. it does take some practice to get the 2 to work together so focus takes longer and more effort but i still enjoy them. I handhold all the shots but if you went from the 300 4.5 it might be a shocker. This guy sometimes is slow to focus (faster than the 300 4.5) but it’s an awesome lens and anyone would be happy to have

bigma if i want to make sure i get all my shots i take this guy. he is heavy and the extension a bit unruely but i got used to it. have had mine about 1.5 years. lens focuses quickly, for the most part it was always extended to 500. the pictures are good. Happy with detail. Bokeh not great but not bad either. I have shot many pictures handheld but it does take its toll after a while. After I got tired of handheld I got the ballhead mount for my monopod. It was ok but got the Manfrotto 393 Heavy Telephoto Lens Support and I like its flexibility.

Both lens are great. it's really hard to say but if i could only have 1 i would get the bigma for the flexibility and range and the DA300 for the bokeh and color.

I was happy for awhile but I want better so just ordered the 500 4.5.

amy
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[mattv]

I went through this same dilemma....what to buy. I originally went with the 150-500 Sigma, but was not happy with the results. Then the Pentax lack of TC's was an issue. Went with the Sigma 300mm 2.8 with a 2X TC......never looked back. A lot of glass, a lot of dough. It is heavy, but well worth lugging around when I need it. Love being able to get shots in low light......

[ilpostino]

I hope it's ok I answer in an old thread instead of making a new one. I currently have Bigma and have seen the DA* 300 for sale for prox ~460 USD. I expect the Pentax will give more crispy pictures.

[RobG]

The DFA 150-450 was the answer for me.