Comparing Olympus 4/3lenses to FX "Full Frame" offerings

Started Jan 25, 2014 | Discussions thread
Jay Ell Regular Member • Posts: 256
Re: Tiger1, I need your help!

Tiger1 wrote:

Jay Ell wrote:

Tiger1 wrote:

Hi, I am a bit puzzled, and as a knowledgeable person I am sure you can help me out:


Let's assume that the pixels of both test systems are the same as the other technology as well. Let's also define that I use ISO 100 and 1/1000s shutter speed for each shot. Also the sensors have the same aspect ratio (4:3).

The questions:

I'll take a picture with 150mm f/2 lens on a 4/3 system, and I choose the f/2.8 aperture. Let's call this P-43.

Then I'll take a FF camera and put on a 150mm lens with f/2.8 aperture and take a picture and crop the picture to the 4/3 frame size - let's call this P-FF43.

Are the output pictures similar or different and if so, in which way? I think they should be identical in this thought experiment, but if not, can you help me out why not?

Of course they are the same! I never said they wouldn't be!

Then I'll take a FF camera and put on a 300mm lens with f/2.8 aperture and take a picture and do no cropping at all. Let's call this P-FF.

If I look at the picture out of this combinatiion at the size of typical piece of paper (A4 or letter size) and compare it to the P-43 and P-FF43, is the picture the same or different to those and if different, in what way? As you teach, the light density should be the same in all these images, and I think I just understand it, but shouldn't the P-FF get more light as it image the lens draws is bigger and it's captured by the bigger sensor area and if so, should the image be less noisy? Or does it matter at all? I am confused, please help me out.

The image on the P-FF will be of superior quality obviously. There are more pixels receiving exactly the same light density each so overall there will be less noise in the image as this noise will be "Zoomed Out" so to speak and made less obvious. The noise per pixel will be the same though.

For the output picture, is the pixel noise relevant? I am puzzled. I thought that only what noise is visible or not in the output picture is relevant? In the above situation, why's the pixel noise relevant or is it?

What would happen to the image quality if the P-FF was used at f/4 and the P-43 at f/2? What about the depth of field? This is difficult for me to understand.

Now that I think of this problem, what about Pentax Q? If I use a 55mm f/2.8 lens on it (P-Q), and output the picture is it just as good as the other cameras would make?

Please help me!

Don't know much about the Pentax Q sensor, its size, pixel count and I definitely don't know how it compares to the imaginary sensor you described above so I cannot answer that question with any surety. Sorry.

What is the sensor is, like in this thought experiement, of similar quality and pixel size as in the other sensors? Would it be better than the P-43 for long range shooting - after all one can connect a 85mm (about 475mm equivalent) with f/1.4 or even f/1.2?

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