Aperture Size matters.


Nov 4, 2010
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#1
Hi,

Not sure where to find, "Search" seems to give endless answer but not really what I had in mind.

I am a M43 user, just like to find out if I am to use a Adapter to a Cannon 50mm F1.4 for example.
Will I get a smaller DOF? A faster prime? Can I get a DSLR FF quailty image with a FF Lens attached?

F-Stops has an equation of -->
Focal Length/Iris of Lens opening = F-Stop
50mm / 35.7mm = F1.4

If were to use a adapter on M43 with the above lens,
Qns
1) Bigger Iris result in more Light into the M43 sensor, resulting a faster lens than prime any M43 fast prime?
2) Physical Aperture is larger than M43 lens, can I get similar DOF
3) If the above 2 points, would it mean M43 sensor can also get near to similar DSLR image quality.
 

kandinsky

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Apr 26, 2008
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#2
If were to use a adapter on M43 with the above lens,
Qns
1) Bigger Iris result in more Light into the M43 sensor, resulting a faster lens than prime any M43 fast prime?
2) Physical Aperture is larger than M43 lens, can I get similar DOF
3) If the above 2 points, would it mean M43 sensor can also get near to similar DSLR image quality.
1) Faster than what? The fastest m43 primes are f/0.95.
2) Nope.

So, if I shoot a portrait with a Micro 4/3 camera and a 25mm f/1.4 lens, and I shoot it at f/1.4. The field of view, depth of field and amount of background blur will be the same as if I’d shot the image at the same spot with a full frame camera, and a 50mm lens at f/2.8. Since Micro 4/3 has a crop factor of 2: 25mm x 2 = 50mm lens for the same field of view, and f/(1.4 x 2)= f/2.8 for the same depth of field. Similarly, 25mm/1.4 = 17.9mm aperture size and 50mm/2.8 = 17.9mm aperture size (so same amount of background blur at the same focus distance).

http://admiringlight.com/blog/full-frame-equivalence-and-why-it-doesnt-matter/
3) Shallow DOF / background blur has little to do with 'image quality'.
 

Octarine

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Jan 3, 2008
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#3
3) If the above 2 points, would it mean M43 sensor can also get near to similar DSLR image quality.
Will any car go faster just by opening the windows?
You need to read up more about what all these term means and which factors affect the technical image quality. At the moment it rather looks 'rojak'.
Don't get obsessed with large aperture. Image quality is defined by a few technical but many non-technical factors (most are behind the viewfinder). It's more efficient to work on the bigger factors if you want to improve image quality.
 

Nov 4, 2010
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#5
Will any car go faster just by opening the windows?
You need to read up more about what all these term means and which factors affect the technical image quality. At the moment it rather looks 'rojak'.
Don't get obsessed with large aperture. Image quality is defined by a few technical but many non-technical factors (most are behind the viewfinder). It's more efficient to work on the bigger factors if you want to improve image quality.
Nope... Open wrong things on car will sure slow down the car performance... Add air resistance.... Open up slightly more air intake, that might help... Hehehe... Actually I am not really obsessed by the large aperture, just happen to see some articles on using a FF lens on M43, so just kept me thinking, by allowing more light in with a bigger opening might... Lower ISO requirement, improve noise... Since with bigger opening and a fix focal length though might result in smaller DOF... Newbie and noob questions... Sorry ah...
 

darrrrrrrrrr

Senior Member
Sep 19, 2006
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#6
Nope... Open wrong things on car will sure slow down the car performance... Add air resistance.... Open up slightly more air intake, that might help... Hehehe... Actually I am not really obsessed by the large aperture, just happen to see some articles on using a FF lens on M43, so just kept me thinking, by allowing more light in with a bigger opening might... Lower ISO requirement, improve noise... Since with bigger opening and a fix focal length though might result in smaller DOF... Newbie and noob questions... Sorry ah...
Using a ff 50/1.4, a aps-c 50-1.4 and a m43 50/1.5 will theoretically give you the same DOF, shutter speed and iso (without going into specifics about T stops). Yes there is more light coming in, but a lot of it is not captured as the m43 sensor is smaller. More light overall, but same per unit area.

You can slap on a "speed booster" (go google that) that can achieve what you're looking for, but unless you have these lenses lying around, i think its better to invest in the excellent native lenses.

Furthermore, modern lenses incl m43 are sharp and contrasty, while older manual lenses are less sharp n contrasty. So unless u're going for that look, your photos might look worse, esp from a newbie standpoint.

Finally, are you comfortable with manual focus, esp for shallow DOF situations which is presumably the look you're going for? Not easy esp for moving subjects.

I'd spend my money on a pana 20/1.7 and oly 45/1.8. Plenty of blurry backgrounds to be had.
 

Octarine

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Jan 3, 2008
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#7
Actually I am not really obsessed by the large aperture, just happen to see some articles on using a FF lens on M43, so just kept me thinking, by allowing more light in with a bigger opening might... Lower ISO requirement, improve noise... Since with bigger opening and a fix focal length though might result in smaller DOF... Newbie and noob questions... Sorry ah...
It's ok to ask questions, nthing wrong with that.
But do think about the outcome: pictures where only a very small portion of the subject is in focus while everything else is blur (to a varying degree). Does this show the beauty or specifics of the subject? Does it tell a story?
I have seen such attempts in food photography, portraits and other genres and rarely it was pleasing. It rather shows that the photographer got carried away over technical games and forgot the main purpose (or never defined it). Using the DoF caclulators you can check for yourself the resulting DoF area under your specific conditions (focal length, aperture, sensor size, distance). Subject isolation is a tool to be sued in composition, it's not the purpose of the picture.
 

kandinsky

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Apr 26, 2008
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#8
so just kept me thinking, by allowing more light in with a bigger opening might... Lower ISO requirement, improve noise... Since with bigger opening and a fix focal length though might result in smaller DOF...
It really depends on what you're comparing to and how you're comparing it.
What lens are you using with your current MFT setup?

If you're comparing a FF 50/1.8 and MFT 25/1.8, any increased amount of background blur is more likely due to the resulting 100mm (after MFT 2x crop factor) FOV on the FF 50m/1.8. You are then comparing a 50mm vs 100mm. Apples to oranges.

The 1.8 can help with light gathering if you're comparing it with 2.8 lens. E.g., When I use a Nikon 50mm/1.8 on my GH3, it's slightly more than 1-stop faster than the native MFT 35-100 f/2.8. But if you're comparing to another native f/1.8 lens, the exposure should be fairly similar.

Here's a rough comparison with a couple of OOC jpegs, resized, no other adjustments. Took some quick shots when I had a couple of minutes to spare this afternoon... could only manage 49mm ;p

 

Last edited:

kei1309

Senior Member
Apr 12, 2010
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#9
Bigger is Better. That's why men and women photographers alike love lenses with BIG maximum apertures
 

Nov 4, 2010
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#10
It really depends on what you're comparing to and how you're comparing it.
What lens are you using with your current MFT setup?

If you're comparing a FF 50/1.8 and MFT 25/1.8, any increased amount of background blur is more likely due to the resulting 100mm (after MFT 2x crop factor) FOV on the FF 50m/1.8. You are then comparing a 50mm vs 100mm. Apples to oranges.

The 1.8 can help with light gathering if you're comparing it with 2.8 lens. E.g., When I use a Nikon 50mm/1.8 on my GH3, it's slightly more than 1-stop faster than the native MFT 35-100 f/2.8. But if you're comparing to another native f/1.8 lens, the exposure should be fairly similar.

Here's a rough comparison with a couple of OOC jpegs, resized, no other adjustments. Took some quick shots when I had a couple of minutes to spare this afternoon... could only manage 49mm ;p
Thank you so much for the explanation with pictures... Much clearer now.... Just one more thing pop out of my mind... So can I say that ... Example I use a 50mm F1.8 nikon lens (for full frame) with adapter on a 4/3 is the same as I use a 50mm F1.8 (4/3 lens, example only) on a m4/3.... Or is another apple to orange thingy.... Cos the iris of the lens in a FF is 3x the physical size of a 4/3 lens. Than again the 4/3 sensor size is fixed.... Sorry... Problem kid... With many problematic questions...
 

Nov 4, 2010
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#11
Bigger is Better. That's why men and women photographers alike love lenses with BIG maximum apertures
Erm.... I prefer small in size and big in performance.... Hahaha.... Hard to coexist...
 

kandinsky

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Apr 26, 2008
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#12
Example I use a 50mm F1.8 nikon lens (for full frame) with adapter on a 4/3 is the same as I use a 50mm F1.8 (4/3 lens, example only) on a m4/3.... Or is another apple to orange thingy....
It is 'the same' in the sense that both should give you similar Angle of View and exposure.

For further reading: http://josephjamesphotography.com/equivalence/#introduction
 

iluvs90

Senior Member
Apr 11, 2010
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#14
Thank you so much for the explanation with pictures... Much clearer now.... Just one more thing pop out of my mind... So can I say that ... Example I use a 50mm F1.8 nikon lens (for full frame) with adapter on a 4/3 is the same as I use a 50mm F1.8 (4/3 lens, example only) on a m4/3.... Or is another apple to orange thingy.... Cos the iris of the lens in a FF is 3x the physical size of a 4/3 lens. Than again the 4/3 sensor size is fixed.... Sorry... Problem kid... With many problematic questions...
you may just be better off investing in a very good and fast Olympus 50mm f2.0 Macro lens which will be usable on a m43 with an adapter.
http://www.dpreview.com/lensreviews/olympus_50_2_o20
 

Shizuma

Senior Member
Mar 19, 2012
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#15
at the risk of going off topic and without any innuendo
wise man tell me
it's not how big you've got
but how you use it.
size isn't everything

I've seen plenty of shooters doing f1.4 but both eyes of subject out of focus during portrait shoot
 

Nov 4, 2010
85
0
6
#16
at the risk of going off topic and without any innuendo
wise man tell me
it's not how big you've got
but how you use it.
size isn't everything

I've seen plenty of shooters doing f1.4 but both eyes of subject out of focus during portrait shoot
Could not agree more... Very true...
 

Octarine

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Jan 3, 2008
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Pasir Ris
#17
I've seen plenty of shooters doing f1.4 but both eyes of subject out of focus during portrait shoot
And the next thing is to blame the equipment and call for the esoteric spirits of lens calibration, cursing service center staff for not finding any fault and resorting to purchase horribly overpriced calibration tools from Internet.
Because it has to be a technical fault, no doubts.
 

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