Low light + 85mm 1.8 ---> 1/160 not enough?

Ah, you still cant see them? ok, here you go:

Sharp enough for me:

HTTP response: NOT FOUND | MIME changed to 'image/png'

HTTP response: NOT FOUND | MIME changed to 'image/png'

HTTP response: NOT FOUND | MIME changed to 'image/png'

HTTP response: NOT FOUND | MIME changed to 'image/png'

The images were being intercepted by Ad Blocker Plus. I guess the host used has been blacklisted.

Now I've bypassed the filter I can load the images. The "not steady enough" one looks like it could be a front-focus issue. The "motion blur" one is exactly that, but I can't get the EXIF info to see what's going on.

They are all shot at f1.8, 1/160 at ISO 3200. I can see the motion trail when zooming into the "not sharp enough" one. You can see it on the wood beam under his arm.

Damn I wish there was a 85mm f2.8 with IS except the whites lenses.

I've noticed that the Sigma 17-50mm f2.8 OS have better resolution wide open than the 50mm f1.4. Coupled with the OS, good reviews and somewhat low price, the Sigma would be an excellent low light lens.

1/160 and crop factor is cutting it close. All lenses should have IS, or at least the body... I hate shooting non stabilized because it's another factor I have to deal with, and dragging the shutter... forget about it.

If sony makes their FF dslr with in body stabilization, it would be worth a look...

Pentax? The ISO noise is as good as the 5d mark ii I believe. Also they have nice little pancakes lenses and who doesn't like pancakes at a fair price?!

What is strange is the release of the 2 wide angle IS lenses. 24 and 28mm. 50 and 85mm would have been a bigger hit even at 800$ each.

Unless they are greatly cropped, and setting aside the possibility of a bit of front-focusing, according to the rule of thumb, the 'average' user should be able to obtain images immune from camera shake, hand-held with no IS, with 85 mm FL on APS-C with a shutter speed of around 1/125 or quicker. If you are not able to achieve this, you should be looking at your technique, in particular how you are holding and bracing the camera/lens, how smoothly you are pressing the shutter release, and even how well you are controlling your breathing.
In fact, it seems you are already aware of the problem:

Earwax69 wrote in post #14905612
Clearly I am not steady enough. But I have to admit that I tought I would be safe at 1/160 and didn't stop my breath or steady my arms against my chest or anything.

Practise, practise, practise.

Earwax69 wrote in post #14907766
Damn I wish there was a 85mm f2.8 with IS except the whites lenses.

Don't forget about your 15-85 and 55-250. Although they may lose out in terms of maximum aperture, they may gain through their IS, especially for essentially static subjects.

I did test those lens today in a dark room. It kinda come to the same. IS work well for both, giving me same exposure at 1/30, f5.6 (15-85) and f4 (55-250), ISO 3200. However I feel the 1/30 will blur any moving person. It's ok for some shots, not really for others.

The 55-250 hunt a bit more though. The AF is slower and noisy. However it might have the best low light performance at 70mm F4 + IS.

I'll go shoot again soon and try to refine my technique. I should also have a bit more light available in a city. I'll try my 50mm f1.8 too. It's been a while I didn't use it. If the 50mm feel great, I'll get the f1.4.

As xarqi said

Two things are always moving, you and camera, and subject. IS only takes care of one element of the situation.

xarqi wrote in post #14906319
What leads you to this peculiar conclusion?

Logic. It's a numerical question, there's no interpretation required except in what you would deem an acceptable shutter speed for a pixel of a reference size. The sensor doesn't know it's cropped; the amount of blur recorded will be the same for any given movement on two bodies with pixels of the same size.

KnightRT wrote in post #14916393
Logic. It's a numerical question, there's no interpretation required except in what you would deem an acceptable shutter speed for a pixel of a reference size. The sensor doesn't know it's cropped; the amount of blur recorded will be the same for any given movement on two bodies with pixels of the same size.

Ah! All is explained. I can see where your logic has led you astray.

There is no blur until an image is printed or displayed. The magnification applied to reach a certain size depends on the sensor size and the print/display size. Images from a smaller sensor will need to be magnified more, hence any blur will be more apparent. Accordingly, the rule of thumb must be modified to take into account the sensor size.

@KnightRT: I understand what you mean. However as, in the end, the image is "zoomed in" by 1.6x, any move inside that window will also by amplified by 1.6. For exemple, a dot take 2sec to pass from left to right of my screen. If I zoom 2x into my screen, the dot will take exactly 1sec to pass from left to right even if the dot is not moving faster in reality.

We do need to account for the crop sensor when calculating our shutter speed needs.

Earwax69 wrote in post #14907766
They are all shot at f1.8, 1/160 at ISO 3200. I can see the motion trail when zooming into the "not sharp enough" one. You can see it on the wood beam under his arm.

Damn I wish there was a 85mm f2.8 with IS except the whites lenses.

I've noticed that the Sigma 17-50mm f2.8 OS have better resolution wide open than the 50mm f1.4. Coupled with the OS, good reviews and somewhat low price, the Sigma would be an excellent low light lens.

You could have 6 stop IS on the 85mm, but if you have subject motion blur, it won't help stop that at all. Others have been saying this too.

You can easily stop your own handshake blur without IS, just get a monopod, or brace yourself against a tree or wall. However none of that will work if your shutter speeds are too slow to stop whatever you are aimed at.

You may think that certain speeds will stop motion, but until you have experiences such as this, you won't know for certain.

For example, you would think 1/250th would be able to stop a slow dance, but here is a shot I screwed up on because just her hand moving through the air slowly wasn't captured very crisply at 1/250th. Even at 1/500th it was questionable, so 1/160th shooting at people who move could very well be a recipe for disaster if you want crisp shots.

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

It still a very nice photo. Not screwed at all..!

I dont know why, tonight I am dreaming of Full Frame cameras and 135L...

xarqi wrote in post #14916411
There is no blur until an image is printed or displayed.

This is not correct. Printing is immaterial to how the image is recorded. If you have have a full-frame 22 MP camera and a crop-frame 8 MP with same focal lens and you move them in the same way, they'll show exactly the same level of blur at the pixel level. It'll be as if you took the full-frame file and simply removed the edges. The final scene will be different, but the blur won't.

@Earwax - You're not zooming, you're cropping. Just because you can't see the other sections of the frame doesn't mean your object is moving twice as fast.