[Barry Pearson]

Just received my Sigma 18-300 an hour ago and have been taking a few shots with it on my K-1 II. I have been using the inside of my grand piano for test shots so far. The lens seems very good in its native APS-C mode (crop mode).

But it is only f6.3 at 300mm and the ISO is ramping up to 8000-25600 (I have my ISO set to AUTO 100-25,600). This is with all ceiling lights on and daylight through the windows as well. The piano lid is obstructing a fair amount of light (shade). I will have to mount my Shanny 600 flash to get proper lighting.

Tried with the Tamron 1.4x TC as well. The autofocus definitely hunts in those conditions. There is vignetting visible even in the viewfinder. Lightroom cannot fully correct it even with the max vignetting correction (200) . In APS-C shots (without TC), LR can fully correct the vignetting (it automatically detected the correct lens profile for the Sigma 18-300).

Not sure yet if the TC is hurting the sharpness or not, it's not obvious from the few shots I looked at so far, and really hard to tell with the very high ISO value. Definitely need to retake the shots with flash to get a better sense and will post them then

I look forward to seeing your results.

I've started to see how the D FA 28-105mm behaves with the Pentax DA 1.4x Converter.
Converters have problems, such as amplifying lens faults. But the 28-105mm is pretty good.
The Pentax DA 1.4x Converter isn't designed for FF. But I'm only using the center of the image, so its faults around the edges will be cropped off.
With the 28-105mm at 105mm, add the Converter and it is the equivalent of 147mm In other words, just a factor of 2 from 300mm.

(I've just found that I have a Tamron 1.4x Pz-AF MC4 Converter stored in a drawer! Is that the same as yours?)

This is getting interesting!

[mikesbike]

Thanks. I will take a look more in detail at your shots. Just received my Sigma 18-300 an hour ago and have been taking a few shots with it on my K-1 II. I have been using the inside of my grand piano for test shots so far. The lens seems very good in its native APS-C mode (crop mode).

But it is only f6.3 at 300mm and the ISO is ramping up to 8000-25600 (I have my ISO set to AUTO 100-25,600). This is with all ceiling lights on and daylight through the windows as well. The piano lid is obstructing a fair amount of light (shade). I will have to mount my Shanny 600 flash to get proper lighting.

Tried with the Tamron 1.4x TC as well. The autofocus definitely hunts in those conditions. There is vignetting visible even in the viewfinder. Lightroom cannot fully correct it even with the max vignetting correction (200) . In APS-C shots (without TC), LR can fully correct the vignetting (it automatically detected the correct lens profile for the Sigma 18-300).

Not sure yet if the TC is hurting the sharpness or not, it's not obvious from the few shots I looked at so far, and really hard to tell with the very high ISO value. Definitely need to retake the shots with flash to get a better sense and will post them then.

Now, it's time for me to get the our three cats in their kennel for vaccinations. Wish me luck ! One of them got so scared on tuesday that I gave up. Second attempt, now with my husband's help.

Your choice for the Sigma 18-300mm is a good one for your wants, as I see it. Your choice is in line with the point I was actually trying to make. A big, slow FF 28-300mm f/6.3 superzoom is inappropriate for most high-quality FF DSLRs. Superzooms are most useful for event shooting, in good lighting or with flash, since one can frame a WA shot and then immediately go to a closeup shot. They are a poor choice for low-light use without flash. Their slow aperture would require bumping up ISO which would reduce effectiveness of the camera's low noise capability. One would be as well off or better with a superzoom on a K-70.

With the K-1, however, one can switch to APS-C mode and benefit from use of an APS-C designed superzoom. To get an image comparable to 300mm with a FF shot, one can then shoot at only 200mm, where the lens is not as slow, and does not require as much bumping up of the ISO. As far as resolution, it would not be comparable to the APS-C 24mp bodies, but so what? Superzoom lenses will not deliver the difference in resolution anyway.

[madbrain]

(I've just found that I have a Tamron 1.4x Pz-AF MC4 Converter stored in a drawer! Is that the same as yours?)

Yes, same one.

[madbrain]

Your choice for the Sigma 18-300mm is a good one for your wants, as I see it. Your choice is in line with the point I was actually trying to make. A big, slow FF 28-300mm f/6.3 superzoom is inappropriate for most high-quality FF DSLRs. Superzooms are most useful for event shooting, in good lighting or with flash, since one can frame a WA shot and then immediately go to a closeup shot. They are a poor choice for low-light use without flash. Their slow aperture would require bumping up ISO which would reduce effectiveness of the camera's low noise capability. One would be as well off or better with a superzoom on a K-70.

With the K-1, however, one can switch to APS-C mode and benefit from use of an APS-C designed superzoom. To get an image comparable to 300mm with a FF shot, one can then shoot at only 200mm, where the lens is not as slow, and does not require as much bumping up of the ISO. As far as resolution, it would not be comparable to the APS-C 24mp bodies, but so what? Superzoom lenses will not deliver the difference in resolution anyway.

Well, the old FF 28-300mm superzooms aren't really that big. As I mentioned earlier in this thread, the (defective, only shoots at highest f-stop, ie. almost closed) Sigma 28-300 FF lens I got on Amazon is smaller and weighs the same as the D FA 28-105. So I don't believe they have to be big. How inappropriate they really are for an FF body would be good to see in pictures.

The IQ may well be better on K-70 with a modern APS-C superzoom vs K-1 II with old FF superzoom. It would be great to see an actual comparison, IMO. I still don't want to carry two bodies though, as I only have two hands and mostly need both to shoot with one camera. That K-1 II with a superzoom + grip + flash is one heavy beast

Agree with you those superzooms don't do well in low-light, no matter the sensor. Flash only helps if you are zooming in something nearby. It doesn't help at all when you are zooming on something far, like, say, the shots I have been taking from hotel rooftops at night on vacation. At that point the high ISO comes in. I felt a bit limited by the K-30 with superzoom lens in those cases. I could have swapped for a better long lens, if only I owned one I still don't own a long prime lens. I believe my Sigma 70-300 (FF) zoom should be better than any superzoom at 300mm, whether FF or APS-C superzoom.

Anyway, I need to get back to my test shots now. I just took shots with the D-FA 28-105 at both 18 and 105mm in FF mode, and Sigma 18-300 at 18, 80, 135, 200 and 300mm in APS-C mode. Tested apertures down to f/8 for each.
I wasn't getting consistent exposures with flash, so put the camera on tripod instead, and fixed ISO to 400 .

I am sorting through the shots now. Will take a few more with each lens with the 1.4x teleconverter also. This is harder to keep track of as it doesn't show up in EXIF.

Will add the Sigma 70-300 FF to my test for good measure. Will probably be at it a few more hours.

[madbrain]

OK, I have completed my tests. No Sigma 70-300 in the mix : minimum focus distance is too high, so cannot be compared with the other lenses. This remains true even in "macro" mode.

Here are the shots with the D-FA 28-105mm, both without and with TC, at 28mm and 105mm. Everything at f8 and ISO 400 .
K-1 II with D-FA 28-105, with and without Tamron 1.4x pz-AF teleconverter - Album on Imgur


Here are the shots with the Sigma 18-300mm, both without and with TC, at 18mm, 80mm, 135mm (reported in EXIF at 143), 200mm and 300mm. Everything at f8 and ISO 400 again.
The shots without TC are in crop mode, shots with TC are in FF mode.
K-1 II with Sigma 18-300, with and without Tamron 1.4x pz-AF teleconverter - Album on Imgur

You can see the full resolution for these shots by clicking on each image and right-clicking "view image".

I was shooting in live view, and focusing again for each change of lens, TC and focal length.
I ran into issues with AF with the TC at higher focal length.
For the D-FA 28-105mm, at 105mm with TC, CDAF did not work. I was able to use PDAF (switching out of liveview) to acquire focus. And then got proper focus peaking on the LCD.
For the Sigma 18-300mm, with the TC, at 200mm and 300mm, neither CDAF nor PDAF worked. I had to use manual focus. Again, I got focus peaking confirmation on the LCD screen.

So, the use of the TC definitely has a big detrimental effect on AF with both lenses - more so at longer focal lengths.
However, what I found with the IQ surprised me. I haven't spent too much time pixel-peeping yet, but so far I'm not seeing sharpness degradation from having the TC vs no TC. There is however major vignetting with the TC and the Sigma 18-300, but not with TC and D FA 28-105.
And the combination of the Sigma 18-300 and the TC in FF mode is giving excellent IQ, IMO, better than I could have expected. And certainly much better resolution than in APS-C mode without the TC.

While reviewing the shots, I became aware that there appears to be a single cat hair resting on top of 3 piano strings, very close to the center of the frame. Even after I reviewed the shots, I went back to the piano and could not locate that hair. I counted the strings in the image to see which ones it was resting on. Still couldn't see it. Finally, I took a flashlight to it, and was able to see it. It really is that small. But if you know where to look, it can be seen in almost every shot I took, even the wide angle shots.

Here is a 1:1 crop of what I'm talking about from the D-FA 28-105mm at 105mm (no TC) :


And here is a 1:1 crop of the Sigma 18-300 + TC in FF mode at 300mm :


---------- Post added 07-05-18 at 08:48 PM ----------

BTW, just looked at 4:1 and 8:1 of the 18-300 . That hair can't be seen in the 18mm shot on APS-C. But can be (very faintly) seen on the FF shot at 18mm + TC. Clearly the Sigma 18-300 lens is able to resolve more detail than the K-1 II's crop mode (about 16MP).

For reference, those piano strings are upper middle, and should be between 0.85 and 1mm according to what I read . And the cat hair looks much thinner than the string, perhaps 1/15 of that. That would put the hair thickness at between 56 and 66 microns. I may be off by a factor of 2 or 3 in either direction, but probably not more. This correlates well with what google tells me about cat hair thickness. Hard to fault the optics for picking up something this small, that I can't see with my own eyes with 20/20 vision.

[Barry Pearson]

OK, I have completed my tests. No Sigma 70-300 in the mix : minimum focus distance is too high, so cannot be compared with the other lenses. This remains true even in "macro" mode.

Here are the shots with the D-FA 28-105mm, both without and with TC, at 28mm and 105mm. Everything at f8 and ISO 400 .
K-1 II with D-FA 28-105, with and without Tamron 1.4x pz-AF teleconverter - Album on Imgur


Here are the shots with the Sigma 18-300mm, both without and with TC, at 18mm, 80mm, 135mm (reported in EXIF at 143), 200mm and 300mm. Everything at f8 and ISO 400 again.
The shots without TC are in crop mode, shots with TC are in FF mode.
K-1 II with Sigma 18-300, with and without Tamron 1.4x pz-AF teleconverter - Album on Imgur

You can see the full resolution for these shots by clicking on each image and right-clicking "view image".

I was shooting in live view, and focusing again for each change of lens, TC and focal length.
I ran into issues with AF with the TC at higher focal length.
For the D-FA 28-105mm, at 105mm with TC, CDAF did not work. I was able to use PDAF (switching out of liveview) to acquire focus. And then got proper focus peaking on the LCD.
For the Sigma 18-300mm, with the TC, at 200mm and 300mm, neither CDAF nor PDAF worked. I had to use manual focus. Again, I got focus peaking confirmation on the LCD screen.

So, the use of the TC definitely has a big detrimental effect on AF with both lenses - more so at longer focal lengths.
However, what I found with the IQ surprised me. I haven't spent too much time pixel-peeping yet, but so far I'm not seeing sharpness degradation from having the TC vs no TC. There is however major vignetting with the TC and the Sigma 18-300, but not with TC and D FA 28-105.
And the combination of the Sigma 18-300 and the TC in FF mode is giving excellent IQ, IMO, better than I could have expected. And certainly much better resolution than in APS-C mode without the TC.

While reviewing the shots, I became aware that there appears to be a single cat hair resting on top of 3 piano strings, very close to the center of the frame. Even after I reviewed the shots, I went back to the piano and could not locate that hair. I counted the strings in the image to see which ones it was resting on. Still couldn't see it. Finally, I took a flashlight to it, and was able to see it. It really is that small. But if you know where to look, it can be seen in almost every shot I took, even the wide angle shots.

Here is a 1:1 crop of what I'm talking about from the D-FA 28-105mm at 105mm (no TC) :


And here is a 1:1 crop of the Sigma 18-300 + TC in FF mode at 300mm :


---------- Post added 07-05-18 at 08:48 PM ----------

BTW, just looked at 4:1 and 8:1 of the 18-300 . That hair can't be seen in the 18mm shot on APS-C. But can be (very faintly) seen on the FF shot at 18mm + TC. Clearly the Sigma 18-300 lens is able to resolve more detail than the K-1 II's crop mode (about 16MP).

I'm getting interesting responses on the thread I started at DPReview. Some responses list old non-Pentax K-mount superzooms, or link to them:

Re: Using the D FA 28-105mm lens as a superzoom-equivalent: Pentax SLR Talk Forum: Digital Photography Review

Re: Using the D FA 28-105mm lens as a superzoom-equivalent: Pentax SLR Talk Forum: Digital Photography Review

9. Tamron 28-300/3.5-6.3 Di: Pentax SLR Talk Forum: Digital Photography Review

K-mount superzooms were a lot more common than I had realised.

[madbrain]

Here is a non-test pic of a cat, taken with TC + 18-300 at 300mm . ISO 25,600, f/6.3, 1/60 . For some reason, the PDAF managed to work on this one. Don't think I would get quite this level of detail in crop mode (you can click "view image" in browser to see the full 36MP).



The TC is unfortunately not too useful at night time/indoor for the longest focal lengths. In practice, beyond 200mm (ie. about 280mm with the 1.4x TC), it's extremely hard for AF to work. I have to resort to MF, but I'm not skilled at that at all. About 8 out of 10 shots are out of focus when I use MF. I don't use any non-AF lenses.
I will have to try it outdoors tomorrow.

Overall, I think a native FF 28-300 superzoom would still be preferable in terms of usable AF. But the IQ is already there with the APS-C superzoom + TC, IMO.

---------- Post added 07-05-18 at 11:54 PM ----------

Same cat, no TC, FF mode, at 300mm. Same ISO (25,600). You can see the pretty severe vignetting in the corner, but it works for this frame IMO.
Sharper than without the TC, but I think mostly because better focus was acquired without it, and less shake. Again full 36MP available by right-click/view image in browser.

Re: shake, I think the SR mechanism does not work properly with the TC. It just passes the electronic focal length info from the lens. But that is off by a factor of 1.4 when using the TC. So, for handheld shots, better not use the TC.
Actually, SR was disengaged completely for this shot. It was taken handheld even though the camera was still in "remote control, 3s" drive mode. So the shake is easily explained - not by the TC, but by user error.



Thus, as a walkaround lens, the Sigma 18-300 works fine in APS-C mode. It offers great IQ in FF mode when combined with the TC, but AF suffers badly at longer focal lengths.
Can't conclude about the effect of the TC on SR yet - will have to repeat that with it actually on when handheld.

I still think a native FF 28-300 superzoom, even an old one, will have better AF than the combo of Sigma 18-300 + 1.4 TC (which is like 28-420 FF).
IQ comparison remains to be seen, until I get my hands on a working FF superzoom .

---

Last edited by madbrain; 07-06-2018 at 12:08 AM.

[madbrain]

Just tried the USB dock that came with the Sigma 18-300 too. No firmware update for the lens, still 1.00 . But you can make fine-tune AF adjustments for 4 different focal lengths, and save them to the lens. Not sure if I will ever need this. Was a nice freebie.

Sigma doesn't provide a lens pouch with this lens, but I got one from Adorama in the free accessory package, along with a few cheap filters (I did not have 72mm size) and a cleaning kit.

[Barry Pearson]

Overall, I think a native FF 28-300 superzoom would still be preferable in terms of usable AF. But the IQ is already there with the APS-C superzoom + TC, IMO.

Here is something to consider:

I have just taken several photos with the D FA 28-105mm and both the Tamron and Pentax 1.4 Converters.

The auto-focusing with the Pentax was much better than with the Tamron. I've put the Tamron back into storage, and I'm experimenting with the Pentax 1.4 Rear Converter from now on.

The Pentax 1.4 Converter is well known to vignette on FF with various lenses. And it certainly does with the D FA 28-105mm lens!
But setting the K-1-series camera to square crop mode leaves a 4912 x 4912 image (24 MP), with good even coverage, and an indication in the viewfinder of this square.

I'll be running 2 sets of tests:
With the D FA 28-105mm, set to 105mm, giving actual 147mm, and
With the D FA 150-450mm, set to 450mm, giving actual 630mm

I'll be trying to judge which is better: using the Pentax 1.4 Converter, or not using it and doing more cropping in Lightroom.
If the Pentax Converter gives even a little improvement, it will be worth having with me. It easily slips into a pocket!

[madbrain]

Here is something to consider:

I have just taken several photos with the D FA 28-105mm and both the Tamron and Pentax 1.4 Converters.

The auto-focusing with the Pentax was much better than with the Tamron. I've put the Tamron back into storage, and I'm experimenting with the Pentax 1.4 Rear Converter from now on.

Good to know that there are TCs with better AF out there ! That was the major problem with using the Tamron TC I encountered. But the IQ end results were worth it, IMO.

The Pentax 1.4 Converter is well known to vignette on FF with various lenses. And it certainly does with the D FA 28-105mm lens!

Since you have both TCs, can you say if it vignettes worse than the Tamron 1.4x TC ? For me, with the Tamron TC and the D-FA 28-105mm lens, the vignetting is very manageable in LR. Not fully correctable with the Sigma 18-300 + TC, though. But you still get way better IQ than crop mode - if you manage to focus, that is.

But setting the K-1-series camera to square crop mode leaves a 4912 x 4912 image (24 MP), with good even coverage, and an indication in the viewfinder of this square.

I did not think of trying that. It may work for the Sigma 18-300 lens without TC ... Of course one can question the usefulness of square format. But it helps to see what picture one is really framing !

I'll be running 2 sets of tests:
With the D FA 28-105mm, set to 105mm, giving actual 147mm, and
With the D FA 150-450mm, set to 450mm, giving actual 630mm

I'll be trying to judge which is better: using the Pentax 1.4 Converter, or not using it and doing more cropping in Lightroom.
If the Pentax Converter gives even a little improvement, it will be worth having with me. It easily slips into a pocket!

Can't imagine that you wouldn't get an IQ boost. For me, it was a huge one with the 18-300. And doesn't seem to have hurt with the 28-105 either. If you care care about photographing something really close up, like one 50 microns cat hair on 1mm piano strings, that Tamron TC + Sigma 18-300 is the ticket
I think the crop I posted above was unequivocal.

[Barry Pearson]

Since you have both TCs, can you say if it vignettes worse than the Tamron 1.4x TC ? For me, with the Tamron TC and the D-FA 28-105mm lens, the vignetting is very manageable in LR.

The corner vignetting with the K-1-series, and both the D FA 28-105mm and D FA 150-450mm lenses, is vastly worse with the Pentax TC than with the Tamron TC!

I've come to the conclusion that the Pentax TC corner problem is so tricky to fix in Lightroom that, (at least for now), I simply won't attempt it.
I'll take the easy way out, and set square crop in the camera, then I can see through the viewfinder where the safe area is.

There are probably other crops that would be effective, for example a full-width panorama crop in Lightroom. But there is no visible crop for that purpose. (I suppose I could use other indicators such as the AF boundary as clues).

[madbrain]

The corner vignetting with the K-1-series, and both the D FA 28-105mm and D FA 150-450mm lenses, is vastly worse with the Pentax TC than with the Tamron TC!

I've come to the conclusion that the Pentax TC corner problem is so tricky to fix in Lightroom that, (at least for now), I simply won't attempt it.
I'll take the easy way out, and set square crop in the camera, then I can see through the viewfinder where the safe area is.

There are probably other crops that would be effective, for example a full-width panorama crop in Lightroom. But there is no visible crop for that purpose. (I suppose I could use other indicators such as the AF boundary as clues).

So, were you able to determine if the Pentax TC is giving you an IQ boost in terms of long focal length ?

[Barry Pearson]

So, were you able to determine if the Pentax TC is giving you an IQ boost in terms of long focal length ?

So far, inconclusive. Some cases are worse, some appear to be better. I'm not sure how to predict!

Today I photographed a plane in flight with the 28-105mm + Pentax 1.4x converter. It was simply a test which I expected to fail, but it didn't!

Yesterday I photographed a statue with the same combination. I thought it should be an easy success. But it failed.

I think the problem is that the lenses I was trying the converter on, (28-105mm and 150-450mm), are naturally f/5.6 at the long end, which becomes problematic once the converter is on. If there is low light, the combination is pushed into noise or shake. Some failures were on a tripod with a slow shutter speed, and a 2-second self-timer which switches off SR. But something managed to shake the camera during the slow exposure.

"Work In Progress"!

[Mallee Boy]

As far as a walkaround zoom, I'm quite fond of my Tamron 28-300mm (A06) lens. Probably not top of the heap in terms of image quality, but I haven't noticed any glaring flaws in terms of rendering.

Cautious support for this lens from me as well...haven't had it long but the first results from it are very encouraging. I have friends who are Nikon shooters, d850's and higher, they all have a Nikon 28-300 in their bags, they call it their lazy lens for those times when your just not quite sure what you may need. All have produced excellent images, award winning images, using that lens.

I have high hopes for the tamron 28-300.

[mikesbike]

Something to consider as well- the crop mode does give a larger image in the frame, but not actual magnification, while the addition of a TC does provide additional magnification. But then come the downsides of the additional glass, and yet slower aperture (even higher ISO). I think a better test would be no TC and the Sigma 18-300mm lens at 300mm in FF mode, and at 200mm in crop mode, even though the FF 300mm would still have greater actual magnification. That still would not address the matter of the lens's wider aperture, and thus potentially lower ISO, capabilities at 200mm vs 300mm in dealing with lower light situations.

A resolution test chart would be a good idea, in addition to scenes revealing of noise at wide-open settings.