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08-12-2013, 06:44 AM   #1
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Help on Tele Prime selection

Hi, I'm looking for a long(er) tele prime to add reach to my DA*60-250 for birds and wild life.
As Pentax has only DA*300 which I find to be too close to 250, I have been thinking of getting the Sigma 500mm.
But then I asked my self if I'd be better with Sigma 300mm f2.8 and a decent TC (1.7 or 2.0), which would be lighter to carry than the 500mm.
Anyone; can you confirm if 300mm with TC1.7 IQ is close to or better than Sigma 500mm?
Would FA*300 f2.8 be better choise - if I can find one? (feel free to PM me if you have one for sale)

Bigma has been one option for me also, but it would double the focal length of my DA*60-250 and I find it to be too dark at f6.3 max aperture.

Thanks
Timo


Last edited by reytor; 08-12-2013 at 01:03 PM.
08-17-2013, 05:33 AM   #2
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Anyone?
08-17-2013, 11:38 AM   #3
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I was pretty much in the same situation a couple of years ago.
Bought a Sigma 300/2,8, which turned out to be a very capable lens when used on its own.
Using TC`s inevitably leads to some loss of image quality. Combined with Sigma“s own 1,4 x TC this lens is capable of providing professional image quality when stopped down 1-2 stops. However, wide open the combo does not quite live up to the same expectations.

It all depends on what you need. Image quality at wide apertures may be quite sufficient if you do not crop or print in large sizes. As I provide material for magazines and publications, and do a lot of wildlife shooting - where wide apertures are needed all the time - this simply was not good enough. I ended up buying also the Sigma 500/4,5. I am quite happy working with then both ever since, despite the extra weight and inconvenience. For my use image quality predominates, a different set of priorities might very well take you to another conclusion.
It is not really a surprise for anyone that a telephoto- TC combo will fall somewhat short of the performance of a high-quality supertelephoto prime. It is really up to what your priorities are, and what you are willing to sacrifice in return.

I have written short reviews of these two Sigma“s in the lens review section of this forum.

By the way, nice to see some of my countrymen turning up in somewhat unexpected places

Last edited by PePe; 08-17-2013 at 11:44 AM.
08-18-2013, 07:15 PM   #4
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Thanks for the info Pekka. I suspected that the 500mm is the way to go, but the price is so hefty, I didn't want to make hesitated move.
I only started photography about three years ago and I have done mainly landscapes and still nature, but I want to move ahead to animal world also, which requires new equipment and shooting skills.

Thanks again for your help.
Cheers
Timo

08-19-2013, 01:56 PM   #5
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Hi Timo,

For my purposes, the FA* 300/2.8 + Pentax F 1.7x AFA is a better choice than the Sigma EX 500 f4.5 because of the much shorter Minimum Focusing Distance (2m vs 4m). I like to shoot small songbirds as close as I can get, and this is usually between 2.4 -3.0m. This combination gives me 510mm at f4.8, and I don't really feel that the optics are compromised significantly. With a crop sensored camera, only the center portion of the image circle is used (which is the best section optically with any lens), and the TC further reduces the FOV by magnifying the very center of the image circle, so with this class of lens, the very few optical flaws in the lens are the only real cause of degradation of IQ you will see.

Most super tele shooters tend to shoot at longer distances, and for this, I'd say that the Sigma might be a better choice, but when considering the alternatives, MFD was a always a top priority for me, and I was already used to using the AFA, so at the time, my choice was between a "bargain" grade FA*300/2.8 from KEH (who are very conservative in their condition grading) for $2500 or a new Sigma for $3200. I chose the FA* and have never regretted the choice.

Here are a few examples. All were shot in jpeg ***, NR and sharpened to taste in PP, cropped as noted and dowsized for posting.

This Green Heron was from between 6-7m. Shot with a K-7, FA* 300/2.8 + 1.7x AF + Sigma EX 1.4x APO TC (714mm f6.7). I was setting up to shoot Pied Billed Grebes from long distance when this guy landed and actually started walking towards me. I actually had to carefully back off to get the whole bird in the frame. This was from a tripod so SR was turned off and the FL in the exif shows as 0.


This White Capped Sparrow is from less than 3m, shot with a K20, FA* 300/2.8 + 1.7x AFA. This is a vertical 5x7 crop from a landscape frame. IIRC, this crop used about 1/3 of the frame.


Here's a White Throated Sparrow from about 3m. K20, FA* 300/2.8 + 1.7x AFA + Sigma 1.4x APO TC. This is also a 5x7 vertical crop of a landscape frame using the full vertical resolution.


. . .and a 100% crop SOOC from the lower left portion of the image.


Here's one from the K-5, FA* 300/4.5 +1.7x AFA handheld from about 8m, cropped to 8x10 from around 2/3 of the original frame. The lens is wide open (exif shows f8, but the AFA converts by multiplying the lens f stop by 1.7x and rounding up)


Here's another with the K-5, Canon FD 300/4 L + 1.7x AFA, from a tripod at 3+ m (the MFD of the Canon) I have no idea where the f4 in the exif came from


If there's image degradation from the TC(s), it's not enough for me to notice, much less care about. . .The TC doesn't effect the MFD

I'm sure that some will be tempted to pipe in saying that the AFAs are expensive, but when the alternative is spending $4k+ for a 500/4.5, then $350 doesn't sound like that much. . . and I purchased my 3 AFAs for an average of @ $125 each, so they certainly were a bargain for me. . . Even a DA* 300/4 + a 1.7x AFA will cost less than $2K USD new, and give you a handholdable 510mm f6.8 that will give you quick AF in most any daylight conditions.

If I had the 500/4.5, I'd still want the 300/2.8 for its closer focusing and faster aperture since lighting is not always perfect (I don't set up blinds or use camo), and lugging over 13 lbs of lens in addition to a tripod and gimbal is just not a possibility for me. With 2 bodies, 2x 1.7x AFAs, 2x 1.4x TC, an FA* 300/2.8 and an FA* 300/4.5, and a tripod and gimbal, I have a whole lot of versatility in FL/speed with minimal bulk and weight -- 300mm at f2.8 and f4.5, 420mm at f4 and f6.3, 510mm at f4.8 and f7.7, 600mm at f5.6, 714mm at f6.7, and in a pinch, 867mm at f8.1 (which will only AF in pretty bright light, and I have to set up the forward mounted AFA to infinity focus first) -- all with AF -- sometimes with the focus limiting of the AFA.

Personally, I'm pretty invested in the 300mm+TC concept of longer reach. I have an FA*300/2.8, Sigma EX 300/2.8 APO, Tamron SP 300/2.8 Mdl 60B, FA* 300/4.5, Canon FD 300/4 L converted to K mount, Sigma EX 100-300/4 APO, a Tokina 100-300/4 SD (MF), 3 1.7x AFAs, a Sigma 1.4x APO AF TC, a Tamron F 1.4x AF PZ MC4 TC, and a Tamron SP 140F 1.4x TC that only mounts to Adaptall 2 lenses. The onlu lenses that I have that natively go past 300mm are the Tokina 80-400 f4.5-5.6 AT-X, a Tokina 150-500 f5.6 (which is pretty much a monster, though a decent lens), and a Tamron SP 500/8 Cat. I also am using a Pentax Q with adapted K mount lenses to get more reach than is possible with my DSLRs, but that's a different story. . .

I'm not saying that this is optimal for most people, it's the best of alternatives for me, and something that should at least be considered.

Scott
08-20-2013, 06:01 AM   #6
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Hi scott. You put me back to square one with those very sharp images with your 300mm+TC combo.
The problem is that FA*300 f2.8 is very difficult to find and I'm not sure how Sigma 300 f2.8 handles with TC's
Do you have any examples of Sigma 300 + sigma 1.4x of Sigma 300 + 1.7xAF?

Timo
08-20-2013, 06:28 PM   #7
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QuoteOriginally posted by reytor Quote
Hi scott. You put me back to square one with those very sharp images with your 300mm+TC combo.
The problem is that FA*300 f2.8 is very difficult to find and I'm not sure how Sigma 300 f2.8 handles with TC's
Do you have any examples of Sigma 300 + sigma 1.4x of Sigma 300 + 1.7xAF?
Hi Timo,

Once I obtained an FA*, I noticed that the Pentax was more suited to work with the TCs I have and the AFA. My Sigma is the EX 300 f2.8 APO (pre DG), and wide open, it shows some of that dreamy looking softness which I assume is caused by the lack of digital coatings causing some flare from the internal reflections off the sensor surface. Since I rarely stop down much when shooting with TCs because of the light loss, I decided to shoot the Sigma at its native FL mostly, and use it when I needed the speed and especially when I wanted to shoot handheld because, for me, it's much easier to handle (I'm relatively small with small hands). The "softness" mentioned is actually more a lack of contrast -- the Sigma is very close to as sharp as the FA*, just less suited for TC use for me. The result is that I only have a few examples from early experiments with TCs and the AFA.

Some caveats -- All of the FA* shots from the previous thread were shot from tripods, and all of the following Sigma + TC shots were handheld. With the AFA, there is no data pin information transmitted from the lens, so the SR system requires a FL entry, so SR is correctly calibrated with the AFA, but not with any other AF TC, since the SR system will assume the native FL of the lens without the TC. In any comparison of these particular images, the FA* will win, because it's a slightly better lens, but also because it was shot with a tripod with better lighting, the actual differences between the two lenses is considerably less than these images show. These were never meant to be a comparison of the lens' performance relative to each other. They were only used by me to determine how I could use the respective lenses to best serve my purposes.

With all that in mind, here are a couple of examples, the first with the AFA, and the second with the Sigma EX 1.4x APO AF TC. Both were handheld in jpeg ***, mildly cropped to print aspect ratios, NR and sharpening applied, then resized to post. I reprocessed these because they're 8 years old, and my PP skills and tools have evolved a bit over that time, so at least that aspect of the final images has been equalized a bit.

With the AFA. somehow the exif got stripped, but it was 1/200, f4.5 (f4 at the lens), ISO 1000 (which is higher than I'd usually shoot the K20, but I needed the shutter speed) This is a full height crop to 8x10, so only the sides were cut a little


With the Sigma 1.4x.. This one was shot at 1/200, f3.2 at the lens, ISO 500. This was from very close to MFD as the DOF is really thin.


With this class of lens (Pro quality glass), good TCs really don't degrade IQ enough to matter for most tastes IMO. I don't know if the newer DG Sigmas are better wide open (or even if my Sigma's performance wide open is typical on a digital body), but even if they're not, if you've given up on the possibility of getting an FA* 300 2.8, then there's no real reason to not be satisfied with the Sigma, IMO. There are actually a number of situations where the Sigma is more appropriate to use, and that's why I kept both (I also have a Tamron SP 300/2.8 Mdl 60B, and there are times when it gets the call too).

Scott
08-21-2013, 04:59 PM   #8
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Thanks again Scott for you thorough explanation.
I will try to see if someone here has the Sigma to make a short test.
One of my friends just got the Bigma and he is very happy with it. I will have a possibility to try it soon to figure out how it is doing.
But my mind is still on the prime lenses....

Br.
Timo

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