Is the 150-450mm sharp at 450mm wide open?

Ive been having great fun with the 150-450mm, the ability to zoom while retaining almost or seemingly as good as my DA*300mm for sharpness alone was worth the money.

But on a couple of the few shoot outs I've had the chance to use it on I noticed some of the full zoom images lacked sharpness/contrast or something.

And tonight I finally had turtle dove in the open and this a 100% view of the best the lens could managed on a monopod at 450mm, 1/1600 sec, ISO640 and f5.6

turtle dove 450mm 100 PC f5-6 by Neil Phillips, on Flickr

So I tied again on a pretty static rabbit with 2sec timer on a tripod and these were the results:
450mm, 1/50 sec, ISO400 and f5.6

rabbit 450mm 100 PC f5-6 by Neil Phillips, on Flickr

So I tried f6.3
450mm, 1/50 sec, ISO400 and f6.3

rabbit 450mm 100 PC f6-3 by Neil Phillips, on Flickr

The f6.3 images seems much sharper and better detailed, and the f5.6 almost unusable if cropped or viewed large. Anyone else found this with the lens?

Subject movement, camera movement, atmospheric conditions.....there are all sorts of things that make ultra-telephoto shots difficult. Your 450mm is a 35mm-format equivalent of 675mm on APS-C, which needs a lot of care in shooting.

John's comments on subject movement is very important to this discussion and as any zoologist will explain, wild creatures that are continually faced with attack from predating species actually are in continual scan mode.

Watch a solitary blue tit before it exposes itself to a potential predator attack on a feeder; it will take a minute ot two to scan the field of view by very rapid incremental, almost mechanical movements of it's head in all directions covering almost the full 3D 360 degree field of view before coming into the open.

The movements I referred to as incremental are so precise and rapid they could could be described as "systematic, programmed, high speed scanning".

Examine photos taken of such a subject at 1/60th , 1/125th and so on and you really need to be at about a 1/500th to cope with the physical speed of these very minute but repetetive head movements.

I find regularly on some of my pictures that a bird's body is sharp as a tack but the head can be unsharp, and it is often clearly not linked to depth of field

If you are close enough to a garden bird on a feeder try a flash and like me you will be surprised how our judgment on sharpness can loose calibration a little.

Rabbits and ground living prey species are continually scanning with their years and eyes, flexing the face and head muscles, perhaps a little less conspicuously than the wonderful meerkat , the ultimate " digital scanner"

As regards lenses and the originsl question from NeilP, I have the 200, 300 and 60-250 DA* lenses plus the 150-450; if I had to choose the sharpest lens I couldn'ft because of the other variables in the field John mentioned.

If I was pinned down, in ideal conditions with rigid support and half decent light the 200 is clearly the sharpest but they are all better than I am and how I deal with the conditions.

One thing is sure; if you are not on a " blue sky day" with a 500th at f8 at 200 iso , all those lenses benefit significantly from rigid support and despite being a "monopod man" in the psst my experience is that you cannot beat a bean bag.

A Benbo Tripod does a great job as far as tripods go, but my carbon fibre tripod has been confined to the draw for big lenses coming out only for macro generally.

The monopod is used very carefully depending on what shutter speeds I get.

Finally with a big lens the combination of focus mode, focus field and depth of field, even on small birds is quite complex - I took a long time to improve my understanding of this with the 150-450 ; wide open with the focus fixed on a medium size bird it is possible (if you are close to it) to have the eyes in focus and the tail out of focus, even if you have spot focussed .

Multi point focus mode is somethimg I do not use on birds that are not in flight; in flight yes and I must say the K1 is very good compared to it's predesessors as was/ is the K3II.

But as mentioned above, on static wild life I rarely use anything other than spot focus.

I am tending to consider depth of field issue more and more and regularly, even If I get the minimum shutter speed, will raise ISO to give me more depth of field.

Hope this helps and I am there might be something others consider as a priority to aid sharpness that can help me.

Tomkeet turns in stunningly sharp images of small birds using his 520mm Pentax all the time ; he sets the standard for me so I would love to hear his view.

Regards

Thanks Daronl, Im aware of the above, some of which I have considered could be a factor on the above, but the turtle dove was at 1/1600 sec and it was a clear mild but not warm evening so no heat haze/fog and the person next to me hand held and got a shot of the same bird with no issue.

As for the rabbit, movement was not an issue as it was frozen in one spot like rabbits do, and ona tripod with timer to avoid any motion blur/camera shake issues. And yet all the f6.3 shots were a lot sharper than the f5.6. Here is the serquence below:

f.5.6

2 5-6 by Neil Phillips, on Flickr

f6.3

2 6-3 by Neil Phillips, on Flickr

f6.3

4 6-3 by Neil Phillips, on Flickr

f5.6

5 5-6 by Neil Phillips, on Flickr

(i moved closer)

f6.3

6 6-3 by Neil Phillips, on Flickr

f6.3

7 6-3 by Neil Phillips, on Flickr

Unless the rabbit only moves on f5.6 shots, there is a marked difference between the 2 aperture settings

Don't know what's going on with the Dove but could the rabbit be a focusing issue? you will get a marginally better DoF on the 6.3 shots and that may be why they appear sharper.

Try a focus test and if out try calibrating the lens to the body.

There is an example of 450mm f5.6 here link

Steve

I wondered about that but thought the difference was be negligible? I suppose if its slightly out it wouldnt show at f6.3 but would at f5.6. Looks like I finally may have to micro adjust my lenses!

That's bad Neil. Worse than my 150-500 with a converter on.

The rabbit shots wasn't a good comparison. I wouldn't suggest using the timer on anything that can move, even though the movement may be so small we don't see it with the naked eye. Having said that I did just the same thing last time out for the grebes, with the DA560mm and the 1.4x - 2 sec timer and liveview. That lens hates the teleconverter.

Hi Neil,

If it is clear that this is repeatble under controlled conditions; Eg: taking 20 test shots of a static subject -10 off at 5.6 and 10 off at 6.3 , with the camera fixed on a tripod , with the focus points set at 9, then I agree, there is an equipment issue, most likely the lens.

My 150-450 is tack sharp at 450 mm without conspicuous change in IQ from wide open up to about f16 ; with 5.6 to f9 being as good as a prime lens.

Two images that show how sharp it is;







The dove image, I must say, looks like the lens has not established focus, manually or by AF. I can't say I haven't had a few shots like this on occasions but it is usually tracking a bird moving around in foliage with the wrong AF focus area setting ( expanded 33 points for eg) as I said in my previous post ,

Try the test shots with all variables removed other than the aperture change; If it is repeatble send the lens back for an exchange.

By the way if you are using a filter take it off for the test shots, I once had an issue with the 50-135 DA* which turned out to be a faulty filter and it wasn't a budget priced filter either.

Is the 150-450mm sharp at 450mm wide open?

Grab Shot at F5.6 X 500th (ISO 400) X 450MM