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"f4 & f5.6 on 1"-type cameras are equivalent to F11 and F15"

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Jeff Greenberg

Jeff Greenberg

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Quoted from DPR's Sony RX10-III review;

Then why is anything over, say f8, needed on 1" sensor Sony???!
Would dumping f9-f16 lighten up lenses further?
Or would it allow adding wider, say, f2, even f1.8, specifically
to RX10-IV, ie, trade weight of narrow fstops for wider fstops...?
Any optical engineers reading this?!
 
Last edited:
Jeff Greenberg said:
Quoted from DPR's Sony RX10-III review;

Then why is anything over, say f8, needed on 1" sensor Sony???!
Would dumping f9-f16 lighten up lenses further?
Click to expand...
Unlikely.
Jeff Greenberg said:
Or would it allow adding wider, say, f2, even f1.8, specifically
to RX10-IV, ie, trade weight of narrow fstops for wider fstops...?
Any optical engineers reading this?!
Click to expand...
As I recall the Panasonic cameras with 1" sensors don't allow closing the aperture beyond f/8. Yes, just tested FZ1000 and ZS100 in Aperture Priority mode and f/8 is the limit.

With my RX100 V the limit is f/11.

What is the limit with your RX10 III, Jeff?

--
Phil
 
Last edited:
Jeff Greenberg said:
f16.
Equivalent must be...?
f45???!!! Or?
Click to expand...
I seldom think about such things, Jeff.

BTW .. this page in the DPR review give a good tool for comparing IQ as a function of f-stop for the unit they tested, and with such as the FZ1000.

https://www.dpreview.com/reviews/sony-cyber-shot-dsc-rx10-iii/4

It also at the bottom has a graph of Equivalent Focal Length wide open for several cameras.

My plan is to use my FZ1000 for now, and upgrade to the RX10 IV if it has the same hybrid-AF sensor as my RX100 V.

--
Phil
 
Last edited:
Jeff Greenberg said:
Confused by aperature equivalency chart.
Shows RX10-III leveling off just under f11.
Yet camera offers up to f16.
How can 600mm f16 in camera = 600mm f11 equivalency???
Some law of optics I know not...
Click to expand...
The equivalency is for each lens wide open. So f/11 is with the RX10 III set at f/4. Use the crop factor to calculate (approx. 2.73). So if you set to f/11 the equivalent is about f/44!
 
Jerry R said:
They must be talking about DOF not exposure.
Click to expand...
Yes, this is a common area of confusion. The equivalency has only to do with Depth Of Field. (For my photography the greater DOF is a distinct advantage.)

For lighting purposes an F-Stop is an F-Stop. The only possible problem might be light diffraction due to smaller apertures. Of course the smaller aperture is required because of the smaller sensor size.
 
I was thinking, not to jump from Sony, but now thinking more than before:

fully zoomed, "Is limit of f4 of RX10m3, and limit of f5.6 of upcoming Nikon DL24-500 a substantial concern? Of course RX10m4 may be a game changer, surely wait for it if possible. Nikon only 500mm at f5.6; Sony m3 to 600mm at f4.0, and who knows how nice m4 will be.

I am realizing, if I can see that far, to want something, there is probably enough light.

The Nikon has very effective Dual Image Stabilization. Is that just for video as some cameras, or for both stills and video. That surely could helps with longer shutter speeds, equalizing ISO perhaps.

Nikon lighter weight, ability/trying to hold steady when fully zoomed handheld has to be an asset for shaky me.

Superfast and accurate hybrid AF, Nikon DL's and presumably RX10m4 will help at f5.6

...............

Now, the tricky question: seems diffraction is somewhat relative to IRIS design, so, how are existing and probable Nikon IRIS designs relative to diffraction.

--
Elliott
 
Last edited:
Jeff Greenberg said:
Quoted from DPR's Sony RX10-III review;

Then why is anything over, say f8, needed on 1" sensor Sony???!
Would dumping f9-f16 lighten up lenses further?
Or would it allow adding wider, say, f2, even f1.8, specifically
to RX10-IV, ie, trade weight of narrow fstops for wider fstops...?
Any optical engineers reading this?!
Click to expand...
You are very confused Jeff. Those equivalencies are to get the same depth of field. As the sensor size of a camera increases, your depth of field will decrease. It's physics. So theoretically, you can get the same depth of field with a larger sensor camera by stopping down the lens to that value.

But the question is, would you? The answer is NO.

On most lenses, as you stop down past about f8 or so, you start getting diffraction effects. So you would be trading off DOF with softness.

Larger sensor cameras tend to gather more photons because of the increase in pixel area. You get better low light performance and decreased noise. Your tradeoff will be less DOF than a smaller sensor camera.

There is no perfect camera. Every camera has compromises. So pick the features you want, or have multiple cameras.
 
PC Wheeler said:
Jeff Greenberg said:
Confused by aperature equivalency chart.
Shows RX10-III leveling off just under f11.
Yet camera offers up to f16.
How can 600mm f16 in camera = 600mm f11 equivalency???
Some law of optics I know not...
Click to expand...
The equivalency is for each lens wide open. So f/11 is with the RX10 III set at f/4. Use the crop factor to calculate (approx. 2.73). So if you set to f/11 the equivalent is about f/44!
Click to expand...
 
Jerry045 said:
Jerry045 said:
You are very confused...Those equivalencies are to get the same depth of field.
Click to expand...
Click to expand...
=====

Is this incorrect?:

RX10-III f4 = f11 FF?

RX10-III f16 = f45 FF?
If latter correct, who needs f45 on RX10-III???!!!!
(some outlier macro shooter needing 2" to infinity DOF, maybe)
Therefore, if dropping, say, f10 (~f25 FF) to f16
loses some weight on RX10-III 24-600mm lens
that could then be traded for adding fstop at
wide end (say f2), that f2 would be employed
at times by, IMO, a huge number of shooters?
What I don't know is weight subtracted, weight added...
That where optics engineers reading this might respond...?

What I am ultimately proposing is an RX10-IV with
24-600mm f2-4 with f9 the highest fstop
 
Last edited:
Jeff Greenberg said:
Jerry045 said:
Jeff Greenberg said:
You are very confused...Those equivalencies are to get the same depth of field.
Click to expand...
Click to expand...
=====

Is this incorrect?:

RX10-III f4 = f11 FF?

RX10-III f16 = f45 FF?
If latter correct, who needs f45 on RX10-III???!!!!
(some outlier macro shooter needing 2" to infinity DOF, maybe)
Therefore, if dropping, say, f10 (~f25 FF) to f16
loses some weight on RX10-III 24-600mm lens
Click to expand...
No weight would be saved!
 
Jeff, dumping lower apertures wouldn't make lenses faster. It's simply an aperture system that can close more than one that only went to f8.
 
Jeff Greenberg said:
Quoted from DPR's Sony RX10-III review;

Then why is anything over, say f8, needed on 1" sensor Sony???!
Would dumping f9-f16 lighten up lenses further?
Or would it allow adding wider, say, f2, even f1.8, specifically
to RX10-IV, ie, trade weight of narrow fstops for wider fstops...?
Any optical engineers reading this?!
Click to expand...
I'm not an optical engineer but one doesn't have to be to know that dumping f9-16 would not allow for lighter lenses and would not allow faster f stops. All you would be doing is restricting how far down the existing aperture mechanism could close. Read this for more info.

http://electronics.howstuffworks.com/cameras-photography/tips/aperture.htm


--
Tom
Look at the picture, not the pixels
------------
Misuse of the ability to do 100% pixel peeping is the bane of digital photography.
 
Last edited:
Gary Coombs said:
But remember, that equivalency is ONLY for Depth Of Field and NOT for light. For light an F-Stop is an F-Stop.
Click to expand...
Yes and that confuses the hell out of people. When DPR posted the article they should have emphasized that point right at the beginning because I still see people posting that it affects exposure.
 
elliottnewcomb said:
I was thinking, not to jump from Sony, but now thinking more than before:

fully zoomed, "Is limit of f4 of RX10m3, and limit of f5.6 of upcoming Nikon DL24-500 a substantial concern? Of course RX10m4 may be a game changer, surely wait for it if possible. Nikon only 500mm at f5.6; Sony m3 to 600mm at f4.0, and who knows how nice m4 will be.
Click to expand...
Yes that maximum f5.6 on a 1" sensor is a real concern.
 
Jerry045 said:
On most lenses, as you stop down past about f8 or so, you start getting diffraction effects. So you would be trading off DOF with softness.
Click to expand...
It's not just the lens but the lens/sensor size combo. For FF sensors diffraction isn't a real concern until f16.
 
Jeff Greenberg said:
What I am ultimately proposing is an RX10-IV with
24-600mm f2-4 with f9 the highest fstop
Click to expand...
Jeff, you would gain nothing by limiting to f9. There is no downside to offering smaller f stops, only in using them.
 
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