300mm v 150-450mm

Hi, I don't wish to repeat what has been posted before but any advice would be welcome. I use a K-3.

I've read previous posts regarding the 300mm or the 150-450 and am in the same quandary myself at the moment. I've recently bought a 560mm and been very impressed with the excellent image quality & now thinking of adding one of the others for sports, aviation & wildlife. The 560 while great is just a bit too big & heavy for aviation for me.

I'm told that the image quality of the 300mm would be better than the 150-450 & it's lighter too which helps, but obviously being able to go up to 450mm would be better for the subjects I shoot. Yet am concerned about the extra weight when trying to use hand held and also if there is a reduction in image quality - provided I can hold it steady!

Many thanks

Any way you can visit a dealer and compare them first hand?

For wildlife I use the 560mm and the 300mm. I used to use the Sigma 150-500. The only time that comes out now is at air shows. I have the 560mm on a tripod and handhold the 150-500. I find having the ability to zoom in and out a big advantage at airshows over the 300mm prime.

I don't have a decent Pentax dealer near me so buy my kit from SRS.
Am going through my shots taken at Yeovilton using the Pentax 560mm and Sigma 50-500mm. 300mm images would be small 🤔

the thing to think off as well is are you thinking of going

why dont you have a word with chris and see if he can do you a deal on ether of these lens if you hire them to try you never know you may get the hire price back for them both if you buy the lens
there is no harm in asking he can only say no

Fwiw, I've a Sigma 100 - 300 F4 that I'd be willing to sell, it has suffered with the peeling paint that is usual with this lens, it comes with the original case, box and has been well looked after, open to a reasonable offer.

I can sort images of the lens if u are possibly interested.

Am in Plymouth so getting to SRS is a bit of a trek. I've thought about hiring them although it seems they don't hire out the 150-450.

Maybe I should keep my fingers crossed that Pentax will soon bring out a 400mm lens.

Thanks for that Mike.
Yes, I would've thought the 150-450 would be an ideal range for aviation but do you find the weight an issue?
I know someone posted before on another thread that he found some images he'd taken at 450mm disappointing because they weren't sharp.

Thanks for that. Yes I saw their prices were higher than SRS. Maybe I'll try that.
Having seen Mike P's images, the quality is certainly very good on the 150-450. The 2kg weight is an issue though if hand held.

I don't find the weight an issue but then I am used to carrying this sort of lens around with me anyway ... I detest tripods so always shoot hand held (hence the reason my FA* 250-600mm has been out approximately 5 times in the years I have had it). Yes it would be nice if it were the same weight as the 300mm but you don't have the focal length (which is paramount at airshows ... and I imagine even more so since Shoreham) and just as importantly you don't have the zoom capability.

As for sharpness at 450mm, click on this and then click on the picture to zoom ... I defy anyone to tell me that isn't sharp at 450mm (remember, it's handheld as well). I think the clue might be in the sentence "some" images weren't sharp .. if you get some that are and some that aren't then the lens is obviously capable but the person using it isn't 100% of the time.

Yep that's sharp alright! Excellent set of images.
I thought my Sigma 50-500 was good until I started using the Pentax 560mm - the image is outstanding. But I was making people duck last week when I was using it!
I'd rather not use a tripod for aviation as find it restricting but it's ok with sports I find.

Excellent images Mike and am impressed with the last one which had a converter on too.
Yes, I'd be more than happy if I can read the writing on the aircraft.
I have found I get a far higher % of sharp images with the Pentax lenses than the Sigma even though it has produced some that I'm really pleased with.