[Sigmund]

I've been progressively stepping up to greater focal lengths in affordable zooms in order to get more filling of the frame. From a 50-200 kit lens to the 55-300 and now the Sigma 150-500. 300mm is the minimum for my kind of shooting. The Sigma doesn't do a bad job but often has to be wide open (and fully extended) to have a shutter speed that will capture a moving bird, and the resulting IQ is just adequate. With a grip on the K3 the whole outfit makes for a bit of a work-out during a day's walk.

So the question is whether to go for an affordable prime, in particular the current Pentax 300mm, assuming that the IQ is good enough to allow cropping for a bigger image. This can be teamed up with my Tamron 1.4x teleconverter for more reach.

Also in the frame I guess is something like the Pentax 400mm for the 645, used with an adaptor. That won't have AF and will need stopping down for exposure reading as I understand it. Its 35mm film equivalent length is 260mm.

Is all this trying to have my cake and eat it too? Should I be trying higher ISOs with the Sigma to allow for stopping down to sweeter spot apertures? Coming from film days I've always been 'grain phobic'

[Adam]

If you pair the 300mm F4 with a TC, you'll probably end up with better image quality than your Sigma.

[robgski]

IF you are using a K-3, you should be able to boost the ISO to at least 1600 without grain/noise becoming a problem, even with some cropping, and give you f8-f11 with a reasonable shutter speed. I'd give that a try before giving up on the Sigma, a 500mm lens is very nice to have.

My problem with a 500mm lens is that that it's very hard to get the subject in proper DOF, long lens really flatten out the 3D effect that a closer picture with a shorter lens would not.

[jpzk]

With your K3, I would say the DA*300/4 with the HD 1.4x TC is likely to be the best according to your description.
You won't get to 500mm but cropping from the huge K3 files should bring you close to your goal.

[derekkite]

A few points to consider.

1. Faster and longer is better. But both cost lots of money. There is a reason why people buy 600 f4's for a very high price, or even the 400 2.8. If you want to shoot early morning you need a fast lens. And unless you can smell them, a 300mm is too short. Essentially you have to decide how much you are going to spend then make the best of what you have.

2. Technique is 3/4 of the shot. What I mean by technique is not only handling of the lens and camera, although that is important, but being in the right place at the right time to get the shot you want. It is impossible to get a lens and body combination that can get every shot under every lighting conditions where you can just see the subject in the distance. So technique is finding how to get the best with what you have. Similar to bow hunters; they need to learn how to get very close to the game. A 300mm close in can get extremely nice shots; it is very very hard to get that close in. Technique also means that sometimes you stay home and dream about spending $6k or whatever to get something that would allow you to shoot that day. So decide what you are going to spend, get it and learn how to get very nice results from it.

3. Anything longer than 300mm requires techniques and skills that take a while to acquire. A soft shot at 500mm may be either a crappy lens or be vibration softness. The 150-500 is pretty reasonable at f8. Look at some of the results others are getting with that lens and try to match them. I had one for a year with the K-5 and got some very nice shots. It has it's limitations however. I could reasonably use it four months of the year when the light was high. I live in a valley and it is dark from fall to spring. I found that in most cases I could get similar results with the DA*300 on the K-3 cropped. The 1.4 TC as suggested by Adam is a very good combination

4. Be patient. There are quite a few people here who have made the journey you are embarking on and realize looking back that they sold lenses that they hadn't mastered. The skill required to get a very nice shot of wildlife with a long lens is considerable, but bad results are easy to blame on the equipment. On the other hand, better equipment will get you better shots, but only if you know how to handle them.

5. A solid tripod may get you more improvement for the dollar than anything else. A flash extender is an inexpensive way to get a couple stops of light, getting better results out of a slow lens for not too much money.

6. Learn how to do noise reduction to your satisfaction. You may gain a stop or two of effective shutter speed or aperture by mastering noise reduction. It isn't trivial to learn, because to take it to it's limit you have to understand the noise characteristics of the sensor and the techniques available. It can make a very big difference for not too much money.

There are a few manual long lenses about that get good results if handled correctly. The Tamron 400 f4 adaptall is a nice lens, as are the A400's. The 150-500 is a nice lens as well. A long lens sharp wide open will be expensive even if old and discontinued for the simple reason that they are in demand.

I have the DA*300 f4 and the Sigma 500 f4.5 on the K-3. The new long zoom is very attractive, but I'd have to sell a bunch of stuff to get it, and I'm not certain it would be an improvement.

[wissink]

I hope its okay that I ask this here. Reading this brought up a question I've been pondering. Using a 300 F4 lens and adding a 1.4x TC, the camera still says F4. Now I've read repeatedly that you lose a stop of light. Does this mean that it says F4 and mean F5.6? I'll step it down to 6.3, 7.1, or 8 for sharpness and contrast but are each of those numbers also a stop different? Can someone clarify this for me? Thanks

[watsoncui]

I suggest to try high ISO first. Actually the light is enough so in this situation high ISO should have better performance than in low light conditions.

I have Sigma 150-500 too and in my opinion it is a quite good choice among zoom telegraph lenses.

[crewl1]

Most TC's do not have the electronics to adjust fstop reading from the lens, they just pass through whatever the lens says.
With Pentax the only exception is the Pentax HD 1.4 TC that does report correct aperture value and focal length.
So if I put my DFA100WR f2.8 lens on the HD TC and shoot wide open it will show as F4 @140mm.

I hope its okay that I ask this here. Reading this brought up a question I've been pondering. Using a 300 F4 lens and adding a 1.4x TC, the camera still says F4. Now I've read repeatedly that you lose a stop of light. Does this mean that it says F4 and mean F5.6? I'll step it down to 6.3, 7.1, or 8 for sharpness and contrast but are each of those numbers also a stop different? Can someone clarify this for me? Thanks

[Lowell Goudge]

I have spent a long time looking for fast and light, and for me, this has ultimately resulted in the K300/4 and the 1.7x AF converter, which by the way does correctly pass through modified aperture information if used with an A series lens.

Any of the Pentax 300/4 lenses produces good results with thei converter, but it is effectively F6.9 wide open so yes, you need light, or a K5 to push tie ISO

[Kendigitize]

I'll second the need for good technique. A have a Sears (Tokina) 300mm 5.6 prime lens that I've had ok results with when the light is just right. I have the Pentax REAR CONVERTER-A 2X-S, that I have tried with the 300mm before and the results were bad. Then I tried again yesterday with early morning sun and lighting the birds just right. And nailing the focus just right at 600mm. This was handheld and no editing or cropping. Not the sharpest photo, but I'm surprised there isn't as much CA and fringing and with a tripod I'm sure it would be a tad sharper. For a $25 mint condition 300mm lens and $30 mint rear converter.. I'm happy. This was F8, iso320, 1/125 with a K-30

[Sigmund]

Thanks for the advice all. Much appreciated.

I've been using the Sigma 150-500 for a year now and feel I know it fairly well.

The way I shoot, some options for improving images aren't available or are limited. I don't go out to shoot birds, I shoot them while I'm out - while walking or camping outback or in the bush.

---------- Post added 06-22-15 at 08:33 AM ----------

PS, while reading around this matter I came across this site with some comparisons ... Pentax DA* 300 f4 | Lens Reviews | The Northcoast Photographer

[devouges]

I have used a 70-300mm fa-j for a few years and was happy. I upgraded to the 55-300mm and was happy and satisfied because my bird pictures were. in my opinion, much better.

I have done a LOT of reading and I am finally ordering the prime 300mm F4....... EVERYONE says it is a GREAT move. Just about everyone in the lens reviews say it is MUCH worth the upgrade.

I have ordered mine and I am SO anxious to get my hands on it......

.....now where did I put those tranquilizer pills....

[Sigmund]

Congratulations!

After the advice here and more reading I pulled the trigger on a 2nd hand one from Adorama. It's not in brilliant condition but should functionally be OK. It'll be 5 weeks before it arrives and can be tested. May do some comparos.