Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Olympus dSLR

Reply
 
Thread Tools Search this Thread
Old Aug 4, 2008, 3:40 PM   #21
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Yep. You're right.

It doesn't look like the Minolta MC/MD lens to 4/3's body adapters need optical elements, from what I can see from photos of one.

So, it looks like that would be a good bet (so that you're not degrading image quality if an adapter's optics are poor, like you'd end up doing with some adapters I see for mounting these lenses on a Minolta AF body (if you want infinity focus). lol

JimC is offline   Reply With Quote
Old Aug 4, 2008, 4:12 PM   #22
Senior Member
 
gwillys's Avatar
 
Join Date: Feb 2008
Posts: 247
Default

yes, the adapters work fine. i have a blast with my manual lenses. hey, if you get here in a hour or so, i'll take you to sybil's for dinner, my treat. better hurry
gwillys is offline   Reply With Quote
Old Aug 4, 2008, 4:44 PM   #23
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Thanks for the offer. That sounds real tempting. But, I couldn't make it tonight. We'll have to try and plan on getting together another time.

JimC is offline   Reply With Quote
Old Aug 4, 2008, 9:23 PM   #24
Senior Member
 
Join Date: Jun 2004
Posts: 477
Default

-=edge=- wrote:
Quote:
dnas wrote:
Quote:
-=edge=- wrote:
Quote:
dnas wrote:
Quote:
And remember, because it's a 4/3 sensor, the equivalent is 160-400mm F2.8 !!!!!!!

It opens up a whole world of "obsolete" manual focus lenses!!!

Your statement is incorrect because you lose light with the older lenses
What do you mean???
while crop factor does increase, the F stop doesn't remain the same.
I would disagree....

"It is important to note that neither the light gathering ability of the lens, nor any of its traits are actually affected: a 50mm f2 lens on a 4/3rds body has the same f-stop and depth of field as a 50mm lens on a 35mm camera, but the 4/3rds sensor only records the equivalent field of view of a 100mm lens. "
dnas is offline   Reply With Quote
Old Aug 4, 2008, 10:39 PM   #25
Senior Member
 
gwillys's Avatar
 
Join Date: Feb 2008
Posts: 247
Default

but:
"The 'crop factor' does affect the apparent depth of field of the taken image: with the magnification of 2, the DOF is effectively doubled (again, it is important to note that this perceived effect is due to the FOV 'crop'; the same depth of field is present, but you are viewing it at twice the magnification)."


so in terms of focal length and dof, a 50mm f2 on 4/3 is equivalent to 100mm f4 on ff.
gwillys is offline   Reply With Quote
Old Aug 4, 2008, 11:13 PM   #26
Senior Member
 
Join Date: Jun 2004
Posts: 477
Default

No, I don't think so.

Suppose you have a Full Frame DSLR, and a 3/4 DSLR, and each one has an identical 50mm F1.2 lens. Each DSLR is 10Mpixel, and each is set to ISO 100.

Since the lenses are identical, the Focal ratio is set to F1.2

This means that the amount of light reaching the sensor plane is the same, because the lenses are the same. However, the full frame sensor is 4x larger in area, meaning that each pixel receives 4x as much light. HOWEVER, the two sensors are BOTH balanced for ISO 100, so each pixel is set to the same SENSITIVITY. The 3/4 sensor will exhibit more noise, because its area4x smaller. This is true because the F-stop of lenses is a fixed by the geometry of the LENS, NOT by the size of the sensor.

If you crop the image from the full frame sensor later, it still DOESN'T change the F-stop of the originalLENS.

So each camera will work as ISO 100, F1.2 lens. In the full frame, it results in a 50mm shot. In the 4/3 camera, it results in a crop giving a field of view equal to 100mm.


dnas is offline   Reply With Quote
Old Aug 4, 2008, 11:27 PM   #27
Senior Member
 
Join Date: Jun 2004
Posts: 477
Default

gwillys wrote:
Quote:
but:
"The 'crop factor' does affect the apparent depth of field of the taken image: with the magnification of 2, the DOF is effectively doubled (again, it is important to note that this perceived effect is due to the FOV 'crop'; the same depth of field is present, but you are viewing it at twice the magnification)."


so in terms of focal length and dof, a 50mm f2 on 4/3 is equivalent to 100mm f4 on ff.
So what you're saying is that if you take a shot on a FF DSLR with a 50mm F1.2 lens, print the result, then cropthe sides off it, you have changed the DOF??
dnas is offline   Reply With Quote
Old Aug 5, 2008, 12:06 AM   #28
Senior Member
 
boBBrennan's Avatar
 
Join Date: Aug 2005
Location: Arlington, Texas USA
Posts: 3,565
Default

.............I've read all this and it's gone way over my head, but I really like seeing G's pictures so keep teasing a bit with those.

Harj, in regard to your original post to start this thread......... "I don't know, maybe".
boBBrennan is offline   Reply With Quote
Old Aug 5, 2008, 12:43 AM   #29
Senior Member
 
-=edge=-'s Avatar
 
Join Date: Jan 2006
Posts: 220
Default

dnas wrote:
Quote:
-=edge=- wrote:
Quote:
dnas wrote:
Quote:
-=edge=- wrote:
Quote:
dnas wrote:
Quote:
And remember, because it's a 4/3 sensor, the equivalent is 160-400mm F2.8 !!!!!!!

It opens up a whole world of "obsolete" manual focus lenses!!!

Your statement is incorrect because you lose light with the older lenses
What do you mean???
while crop factor does increase, the F stop doesn't remain the same.
I would disagree....

"It is important to note that neither the light gathering ability of the lens, nor any of its traits are actually affected: a 50mm f2 lens on a 4/3rds body has the same f-stop and depth of field as a 50mm lens on a 35mm camera, but the 4/3rds sensor only records the equivalent field of view of a 100mm lens. "
because the adapter doesn't affect the light either i suppose, given that it, nor the lens were designed for the camera, but couple them together and viola, a perfect f1.2 lens without any loss of light or speed....:lol:
-=edge=- is offline   Reply With Quote
Old Aug 5, 2008, 12:54 AM   #30
Senior Member
 
Join Date: Jun 2004
Posts: 477
Default

-=edge=- wrote:
Quote:
dnas wrote:
Quote:
-=edge=- wrote:
Quote:
dnas wrote:
Quote:
-=edge=- wrote:
Quote:
dnas wrote:
Quote:
And remember, because it's a 4/3 sensor, the equivalent is 160-400mm F2.8 !!!!!!!

It opens up a whole world of "obsolete" manual focus lenses!!!

Your statement is incorrect because you lose light with the older lenses
What do you mean???
while crop factor does increase, the F stop doesn't remain the same.
I would disagree....

"It is important to note that neither the light gathering ability of the lens, nor any of its traits are actually affected: a 50mm f2 lens on a 4/3rds body has the same f-stop and depth of field as a 50mm lens on a 35mm camera, but the 4/3rds sensor only records the equivalent field of view of a 100mm lens. "
because the adapter doesn't affect the light either i suppose, given that it, nor the lens were designed for the camera, but couple them together and viola, a perfect f1.2 lens without any loss of light or speed....:lol:
The adapter doesn't affect the light, because the lens is the SAME distance from the sensor as it would have been originally from the film plane.

The F1.2 lens will be the sameas it wouldif it wasattached to any OTHER camera. The parameters of the lens dictate its F number, NOT the device it's attached to.
dnas is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 10:51 PM.