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Forum: Pentax K-1 & K-1 II 05-12-2018, 05:19 PM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

Oh, I agree Sandy's image is impressive, only saying that how impressive at 2MP or even 8MP isn't the same as impressive at 36MP.

I don't mind buying a prime lens - hardly ever used the 20mm end of my Sigma 10-20 . But lack of AF is really a big issue for me in general. Especially with the AF in K-1 II being so good.
I just don't like to take the time to MF, and I'm also not very good at it.

That said, the price for the Samyang 14mm certainly is right - $279 new right now on Amazon. IRIX is almost double that .
I would definitely buy the Samyang if it was AF, but they are not doing any AF for Pentax.

I tried my Sigma 10-20 last night at 12mm indoors, shooting a bookshelf. Both in crop mode, and in FF mode with a Tamron 1.4x AF TC.
The image just isn't sharp enough, even without the TC. The TC doesn't make the image worse, just makes the AF worse.
Maybe I need to repeat my tests under different conditions. I have never had any real issues with my outdoor landscape shots with that lens.
But it is most useful indoor in small spaces, IMO, when standard zoom isn't wide enough. That's the main reason I want a wide lens.
In recent years, I haven't used my Sigma 10-20 very much. It is a bit bulky. A wide prime lens makes more sense to me than a zoom, as it should be smaller and have better IQ. I just want one that is AF.
That doesn't seem to exist for Pentax FF, unless I'm mistaken.

Seems like Sigma has a 10mm/2.8 APS-C prime . Goes for around $600, though. Wonder how much it would vignette with the 1.4x TC, and whether IQ would be good enough. Never mind - it's a fisheye.

Forum: Pentax K-1 & K-1 II 05-12-2018, 02:40 AM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

Actually not bracketing - just set fixed ISO, Tv mode, and switch shutter speed with a dial to let the camera choose aperture.
Just did these tests. Shot at ISO 3200, shutter speeds between 1/40 and 1s (could not go to 2s because I reached F22 at 1s, which is the smallest aperture on D FA 28-105).
I did only a single shot for each aperture.
My two best shots were at 1/13 and f/7.1, and 1/10 and f/8 . These were the sharpest. There is no blur visible in any shot faster than 1/8 f/9.
Blur only shows up at 100% at 1/5 and f/11 . Gets progressively worse until 1s / f/22.
The widest apertures, wider than f/7.1, actually have significant vignetting in the corners. Probably something that can be easily corrected in post.
For the most usable image, that needs no NR in post, no vignette correction, the ISO3200 1/13 f/7.1 or 1/10 f/8 are the best. Both could be printed large, cropped and enlarged.

Incidently, when I first started my tests, I had set shutter at 1/20 and was surprised to get a blurred image. Actually, my trigger was set to "remote control", which disabled SR in the camera. As soon as I switched it to "single shot", SR came back.
Very obvious the K-1 II SR has a massive effect for this shooter.

Here is the best image at 1/13s :

Or pixel-peep all 36MP from
https://i.imgur.com/EQz0xla.jpg

---------- Post added 05-12-18 at 02:45 AM ----------

The 15-30 is big $$$ though . Wide range seems to be the most expensive to get for Pentax FF.
To that effect, I bought a Tamron 1.4x Pz-AF FF teleconverter on ebay a week ago. I tested it outdoors with my Sigma 10-20 f4-f5.6 DC . It vignettes at 10mm (15mm equivalent), but is usable at 11mm (16.5 equivalent).
That Sigma was the most expensive lens I ever bought, $500 on Amazon ten years ago. The TC was $150 last week. Poor man's wide lens solution. But hey, it's not $1200.
Time to try it indoors now. Will be interesting to see what I can handhold. I wonder if the stabilizer will get confused since it gets the focal length from the electronic contacts, and doesn't know there is a TC in the mix ... That may be a downside of having a TC. Time to find out.

Forum: Pentax K-1 & K-1 II 05-12-2018, 02:00 AM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

I didn't say your image wasn't sharp. I absolutely agree it's sharp. I only said that it can't fully be evaluated at that resolution

I am aware. However, at full resolution, blurring clearly shows in my K-1 II 2s shots, which doesn't show in the K-1 II 0.5s or 0.5s shots.
If you shrink all 3 of these images to HD resolution (about 2MP), they are practically indistinguishable. At 4MP, the 2s looks blurred, others look fine.
But at 36MP at 1:1 resolution with the monitor, you can very clearly see the effect of the shaking in the 2s shot. And to a lesser extent the 0.5s and 1s shots too.
In the 1/40s shot, you can read the titles of all the books, but there is more noise. The point of the stabilizer is to use a lower shutter speed to get more light and a cleaner, sharper image, than you might achieve without stabilizer.
In my case, 2s is not really needed to get enough light. Shooting between 1/4 and 1/20 would produce a picture with less blur than the 0.5s - 2s shots. Ie. it would be a sharper picture.
And it would also have less noise than the 1/40s picture, due to lower corresponding ISO, if aperture was wider. Bracketing in Tv mode, based on shutter speed, might more most sense. That would leave both aperture and ISO up to the camera, though.
Bracketing in Tv mode with fixed ISO would change just aperture as function of shutter speed. I'm actually going to try that now.

So, resolution is related to IBIS, IMO. If you intend to do large prints, or print from crops, then resolution matters. You need to pixel peep for those cases, and have a better IBIS if you have a higher-resolution sensor, than for a small sensor.
Seems like Pentax certainly has that in the K-1 II vs the GX85 sensor :)

Quote:

Oh, stuff it: here it is at full size. Download it from Flickr if you must....

Trinity College library - full size

Do I need a flickr account to do that ? I don't have one. I can't see a way to download the full resolution file.

Forum: Pentax K-1 & K-1 II 05-12-2018, 01:10 AM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

I have had pulse recorded as high as 250 as a teenager in PE class. I am supposed to be dead. My guess is that it was too much vitamin C intake that day, as I take some for my regular colds, and it is known to raise heart rate.

In any case, you didn't post a full resolution image for DPS image. I think it might look slightly different if we could see the full 36MP.

I think all my K-1 II images look fine if downsized to the same as yours. At 4K, all are usable. It's only when pixel-peeping at >4K resolution that the sharpness differences really show. That would be most relevant for large prints and/or crops.

Forum: Pentax K-1 & K-1 II 05-12-2018, 12:29 AM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

So, no one has any comments on this ?

I guess it's the last time I post drunk stabilizer tests to Pentax Forums.

Forum: Pentax K-1 & K-1 II 05-11-2018, 04:42 PM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

With EVF, you have a very limited frame rate, however. Not sure exactly what it is, but I believe 60fps, no more. This may or may not be adequate depending for some fast-moving subjects.

Also, last night, when I was testing my GX85 with long exposures and setting the shutter speed to 2s, I was getting one frame every 2s in the EVF . Very hard to compose your shot that way - at least, it takes more time !

I don't understand why lighter cameras would be easier to handhold for long exposures. I found exactly the opposite, with the K-1 II stabilizer faring way better than the Panasonic GX85 with dual IBIS.

K1-II with grip and lens was 4.4lbs, GX85 only 1.1 lb.

---------- Post added 05-11-18 at 04:45 PM ----------

It really depends what lens and conditions you are shooting. I can handhold a 800mm mirror lens with the K-1 II . Not at 2s exposure, but at 1/15s.
Typical rule of thumb is to use 1 divided by focal length for shutter speed , which would mean 1/800s.
I would have to use very high ISO to shoot at 1/800s with that f8 fixed aperture lens.
I don't think it's correct to say the feature is not necessary with FF.

---------- Post added 05-11-18 at 04:47 PM ----------

My GX85 has both in-body IS and in-lens IS, combind to work together . Panasonic calls it dual IBIS. It fared poorly in my tests last night.
Those 2 stabilizers don't help much with low shutter speed, if you can only see one frame every 2s in the EVF ...

Forum: Pentax K-1 & K-1 II 05-11-2018, 03:17 AM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

OK, here are test shots from the K-1 II .

All with D FA 28-105mm at 28mm and F7.1 . I used TAv mode.

First one, 1/40, ISO 10,000 .

Second, 0.5s, ISO 500 :

Third, 1s, ISO 250 :

Last, 2s, ISO 160 :

I took the best of 5 shots for 0.5s and 1s .
For 2s, I needed at least 15 shots to get it this sharp. The difference is mostly seen when you pixel peep at 100%. At full screen on my 32" 4K monitor the different is difficult to perceive for the first 3 images. The first image has more noise, and the last one is clearly softer.

These are not from PixelShift. I have not tried disabling the SR.

If you click "view image" on each image, at least in Firefox, then click the magnifying glass, you can pixel peep the entire 36MP resolution.

---------- Post added 05-11-18 at 04:13 AM ----------

And here are the tests with the Panasonic GX85, which has dual IBIS, both from the body and the 12-32mm lens.
All shots were taken at 12mm (24 mm equivalent), and f11 . After shooting, I realized I shouldn't have stopped down the lens that much with this small sensor. The UI on the GX85 is still very unfamiliar to me, and it lacks a "Tav" mode, which the Pentax has.
I was having to switch to A mode to set the aperture with the single dial, then back to M mode to set the shutter speed with the single dial. Now that I think of it, the GX85 has a touch screen, and there was probably a way to set the aperture in M mode by touching the screen. But none that I could find by using the dial. Maybe I'll just have to RTFM. I got the GX85 camera only a few weeks ago, and used it mostly for video on tripod so far, or still photos of my cats during daytime. The stabilizer option had been left at the default all along.

First, ISO 25,600, 1/40s :

The field of view is different from the other 3 on this one because I went back upstairs to reshoot at f11 . My original shot at 1/40s was at f3.5 . I wanted all 4 shots to be at the same aperture.

Second, ISO 1600, 0.5s . This was the best of 5 images :

Third, ISO 800, 1s . This was the best of 5 images :

Fourth, ISO 400, 2s . This was the best of about 15 shots :

What's really surprising on this one is that none of the shots at the lower shutter speeds (0.5s, 1s or 2s) look very good at full screen on my 4K monitor, and they are just awful when pixel peeping.
The 1s image looks the best to me at full screen. I could probably have achieved better results at 0.5s with more tries.

The 1/40s shot is also awful, but not due to the stabilizer - wrong choice of aperture, which forced me to use the highest ISO of 25,600 on the camera.
If I was a review site, I would repeat somewhere between f9 or f7. I would also sober up. Anyway, to me, the stabilizer GX85 is just not helping much. I have not tried disabling it. Just night and day with the much bigger K-1 II at identical shutter speed in terms of blur.
I put it on a scale, and the K-1 II with the original battery, plus battery grip, 6 eneloop pros, 2 SD cards, and the D FA 28-105mm with reversed hood weighs 4.4 lbs.
The GX85 with the 12-32mm lens, battery, SD card, and the lens cap attached with a lens keeper weighs 1.1 lbs, a quarter of the weight.
Either I am much better at handling large cameras than small cameras, or the K-1 II really blows the GX85 out of the water in terms of image stabilization, despite being in-body only vs body + lens.
The first theory certainly makes sense, since I have been shooting Pentax for 10 years, usually with a relatively heavy superzoom.
The GX85 was also a $500 camera with two lenses (12-32 and 45-150), where K-1 II was $2400 with one lens (28-105) and battery grip. Huge difference in price.

Again, with these GX85 shots, you can click "view image" and magnifier in Firefox in order to pixel people to the full 16MP resolution.

All shots from both cameras were in RAW - DNG for the K-1 II, and RW2 for the GX85. They were processed to full-size JPGs in Aftershot. The K-1 II profile is one I created from the official K-1 profile. The GX85 profile is the official one from Corel. I didn't apply any kind of processing, all defaults when generating the JPEGs. As you can see, the 12-32 lens has a pretty bad distortion at 12mm. Aftershot doesn't have any lens profile for either the Pentax D FA 28-105 or Panasonic Lumix G Vario 12-32mm, so there was no lens correction applied either.

I don't have an Olympus to compare with, but I sure hope the stabilizer does better than my GX85.

Forum: Pentax K-1 & K-1 II 05-11-2018, 12:21 AM

K-1 stabilization vs Olympus e-m1 mark 1 stabilization: is Oly really that good?
Posted By madbrain

Replies: 66
Views: 6,893

I tried with the K-1 II and 28-105mm. I had to turn off the lights for the bookcase, and stopped the lens down to f7.1, otherwise the K-1 would overexpose with 2" shutter speed on FF sensor even at ISO 100.I did not get any sharp images that I could see by zooming on the LCD screen. Same for 1". Even 0.5" seemed to be borderline. I just looked at the images on my 32" 4K monitor, and the 2" images are actually somewhat usable without doing a 1:1 crop. I'm really extremely surprised.
I did try PixelShift as well at 0.5" shutter speed. When zooming in to pixel level, the 0.5" and 1/40 images are nearly indistinguishable. I'm viewing it in Aftershot Pro which doesn't support PS, AFAIK, but still displays an image. It may just be displaying the first frame. If so, I must have gotten very lucky. I did try PS at 1" and 2" but they looked horribly blurred on the LCD so I deleted them.

Keep in mind my resting heartbeat is >100bpm, I had 300mg of caffeine today, and a fair amount of alcohol at dinner time as well. Pretty much the worst case for shooting long exposures handheld.

Now, the true scientific test would be to repeat the test with the SR off.

I have attached samples at 1/40 , 2" and 0.5" (from the PixelShift file, but probably just the first frame). These have been reduced to just a few KB each by PF so can't really pixelpeep. Edit: removed the files because GPS was on and it was showing in EXIF. Will have to reshoot with GPS off . Probably faster than figuring out how to strip it..

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