Amazing lens, incredible sharpness

Moti wrote:

Great Bustard wrote:

Moti wrote:

Now I hope you do understand the difference between 1/200 and 1/400 and the way it effects motion blur. If not, I'll be happy to make you a drawing.

What I understand is that if you shoot at 75mm f/1.8 1/400 on mFT, I can shoot 150mm f/3.5 1/400 on FF. The result will be the same DOF, and the same total amount of light projected on the sensor, which will result in the same noise for equally efficient sensors (and, for reference, the sensor in my 6D and the sensor in the EM5 are equally efficient, more or less).

So, what was that you were saying about motion blur?

Ok sorry, let me give you the whole pucture. I shoot a lot of classical concerts. My main needs are:

1. Good low light performance.

2, wide DOF to keep the whole orchestra in focuse.

3. High shutter speed to reduce motion blur mainly on fast moving hands.

4. Silent operation

5. Size and weight which start to be an issue because we travel a lot by air for our jobs.

Can you still tick all these points with your 6D and a150mm f/3,5? I doubt it very much.

I'm not talking about which system is better for whom under what circumstances. I am saying that 75mm f/1.8 on mFT is equivalent to 150mm f/3.5 on FF because they have the same diagonal angle of view, and same aperture diameter which means the same DOF and the same amount of light projected on the sensor for a given shutter speed, and thus the same noise for equally efficient sensors.

But, since you bring it up, let's discuss what would happen if there were a 150 / 1.8 IS for FF. First of all, it would be a larger, heavier, and more expensive kit than a 75 / 1.8 on mFT. Secondly, it would put 4x (2 stops more) light on the sensor for a given shutter speed resulting in half (one stop less) noise, albeit with half the DOF. You see, that's the thing that so many don't realize -- noise and DOF go hand-in-hand, regardless of the system.

It's operation could be just as silent as an mFT camera (the 6D, for example, has a silent shutter option). Also, the DSLR would have TTL as opposed to EVF, but both would have LCD -- some would prefer one over the other.  On the other hand, with mirrorless NEX FF on the horizon, we might find that the operational differences vanish.

Now, let's say that there were a 150 / 3.5 IS for FF. What this would do is greatly reduce the size, weight, and cost of the FF system, although the mFT system would most likely still come out ahead on these points, (perhaps the opposite, however, for FF NEX, if such a lens were made).  Either way, the FF system would have no advantage in noise or DOF.

Once again, when I say that 75mm f/1.8 on mFT is equivalent to 150mm f/3.6 on FF, by "equivalent to" I mean they have the same diagonal angle of view, same aperture diameter, which means the same DOF, the same total amount of light projected on the sensor for a given shutter speed, and thus the same noise for equally efficient sensors. I am absolutely *not* talking about size, weight, cost, AF speed, or any other elements of IQ or operation.

And, to send the point home, if you think that 75mm f/1.8 on mFT is not equivalent to 150mm f/3.6 on mFT due to size, weight, cost, operation, etc., then you sure as hell wouldn't claim that 75mm f/1.8 on mFT is "equivalent to" 150mm f/1.8 on FF, since that would only increase whatever differences already exist.

In other words, in your world, no lens on any system is "equivalent to" any other lens on any other system. However, since I have defined how I use the term "equivalent to" over and over in this thread, it is more than clear that I was talking about the visual properties of the photos (in fact, I spelled it out -- more than once), and not the operation, so all this "entertainment" comes from either not reading what I wrote multiple times, or *actively* ignoring it.