Atho
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You are most confused. The Pany has a magnification of 0.25/0.5 while the Oly has 0.21/0.42.
Not the 0.50 vs 0.21difference you proclaimed.
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Using extension tubes with long lens
- Thread starter Trevor Carpenter
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Not the 0.50 vs 0.21difference you proclaimed.
bclaff
Forum Pro
I'm a little confused by your corrections. I see
LEICA DG VARIO-ELMARIT 50-200mm
0.25x (at 200mm 750mm distance)
M.Zuiko ED 100-400mm F5.0-6.3 IS
0.29x (at 400mm 1300mm distance)
I think you're the first person to mention the Olympus 100-400mm in this thread. Interceptor121 was talking about the Panasonic 100-400mm f/4-6.3 and Olympus 40-150mm.
bclaff
Forum Pro
Happy Daze
Leading Member
...that I created a short while ago.
Pedagydusz
Veteran Member
Thank you for the Photons to Photos Optical Primers. I actually was aware of the second (Close-up lens), have not followed all the math but the conclusions are (in this case) what matters. The one about extension is very useful.
Pedagydusz
Veteran Member
Thank you! I also have one interesting image to show about extension in Macro-photography.
This has been in my gallery for years, and is about what we could call the dinosaur of extension: bellows. They are like very large extension tubes, and were totally outdated in recent years, especially with Focus Bracket techniques. The bellows are actually Olympus, with OM mount, and here used with an adaptor with the Lumix GF-1.
Panasonic GF-1, Olympus bellows and an OM lens
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Antonio
ferrer.smugmug.com
This has been in my gallery for years, and is about what we could call the dinosaur of extension: bellows. They are like very large extension tubes, and were totally outdated in recent years, especially with Focus Bracket techniques. The bellows are actually Olympus, with OM mount, and here used with an adaptor with the Lumix GF-1.
Panasonic GF-1, Olympus bellows and an OM lens
--
Antonio
ferrer
Gosto de Fotografia há mais de 40 anos. Comecei com uma Zeiss Ikon Ikoflex, comprada com o primeiro dinheiro que ganhei (ao terminar o Liceu). Depois, as SLR: Praktica, Pentax SP 1000, Olympus, Canon EOS 500 (e várias compactas). Entrei no digital com uma Olympus C2100uz, e depois voltei à...
ferrer.smugmug.com
Pedagydusz
Veteran Member
Result of the shown contraption:
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Antonio
ferrer.smugmug.com
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Antonio
ferrer
Gosto de Fotografia há mais de 40 anos. Comecei com uma Zeiss Ikon Ikoflex, comprada com o primeiro dinheiro que ganhei (ao terminar o Liceu). Depois, as SLR: Praktica, Pentax SP 1000, Olympus, Canon EOS 500 (e várias compactas). Entrei no digital com uma Olympus C2100uz, e depois voltei à...
ferrer.smugmug.com
Happy Daze
Leading Member
This dinosaur once used bellows. You can still buy bellows now but I have never found anyone that makes them with contacts for lenses which would not be that difficult. I think they would sell well, I feel a Kickstarter coming on ...
Trevor Carpenter
Forum Pro
Thanks for posting this. It explains some things that I didn't understand.
Atho
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nothing confusing about what I stated as it’s fairly obvious that the magnifications referred to the 40150 & 50200. I’ll leave to you to figure out which is manufactured by Olympus and Panasonic.
Hope you don’t get too confused again
Happy Daze
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My pleasure, I am pleased that you found it useful.
Eric Nepean
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The number I always use and remember (my field is radio and RF engineering) is 1 foot (30cm) per nanosecond or 1 foot wavelength at 1000MHz.
Interceptor121
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The blur depends only on fstop given the same magnification and I have tested it too
so once the subject size in the frame is the same the depth of field only depends on the aperture
the field of view behind is what is influenced by the focal length the blur isn’t
Interceptor121
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Nope the horizontal view changes from 69mm to 52mm which is around 1.33 with 26mm extension
this is due to the fact the lens at 1.3 meters is shorter than 400mm
the other issue is that you can no longer focus at infinity and you are getting darker images with the camera very slow to focus
if you have nothing else so be it however the benefit is not as much as you think and 33% more is far from 2x you mentioned a long way
with a frame width of 69 mm there are plenty of large moths and butterflies you can shoot
this is due to the fact the lens at 1.3 meters is shorter than 400mm
the other issue is that you can no longer focus at infinity and you are getting darker images with the camera very slow to focus
if you have nothing else so be it however the benefit is not as much as you think and 33% more is far from 2x you mentioned a long way
with a frame width of 69 mm there are plenty of large moths and butterflies you can shoot
Mark Ransom
Veteran Member
Admiral Grace Hopper was well known for giving out 11.8 inch wires at her speeches, calling them nanoseconds. And then going on to explain that they weren't really, because electrons move faster in a vacuum than they do through wire.
Did you actually read my comment before responding?
I already pointed out that at the same subject framing depth of field only depends on the f-stop. What did you think I meant by "I'll need to use f/9 for sufficient DOF regardless of the lens"?
Depth of field isn't the same thing as background blur. In fact, DOF calculator apps usually provide separate figures for both, e.g. dofsimulator.net
Of course the focal length you use can influence background blur. With the same framing and depth of field, shooting from further away with a narrower field of view will magnify the background more (i.e. greater lens compression), leading to a more blurred background in your image.
For example, if I shoot a butterfly on a flower with grass in the background, a long lens might smoothly blur the grass to little more than a green texture, while a wide angle lens at the same f-stop might clearly show every blade. There's obviously not such a difference between 200mm and 400mm, but it's still easily noticeable.
Here's a nice example borrowed from a Bob Atkins article:
He also has a background blur calculator on his site.
Do you really not know this, or are you just arguing for the sake of arguing?
Jack Tingle
Senior Member
Interesting.
I use my extension tubes on my 14-42mm and the 40-150mm. It never occurred to me to put them on the 75-300. So I tried it in the brush along my driveway. No science involved, just hacking away.
75-100mm no extension tubes, but with a crab spider. I have one closer and slightly better focused, but with no crab spider.
75-300mm with 26mm extension tubes
I use my extension tubes on my 14-42mm and the 40-150mm. It never occurred to me to put them on the 75-300. So I tried it in the brush along my driveway. No science involved, just hacking away.
- They work fine.
- Mine are cheap and I'd have to buy a nicer, stronger set before I'd use them on a heavy lens regularly. The 40-150 plastic fantastic does not count as heavy. [Boggle]
- Min focusing distance drops down to a meter-ish.
- Magnification isn't really improved that much, but you can get the magnification from far, far, away.
- Hand-holding a 300mm lens is tricky at this scale.
75-100mm no extension tubes, but with a crab spider. I have one closer and slightly better focused, but with no crab spider.
75-300mm with 26mm extension tubes
Eric Nepean
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Mark, a very neat demonstration - I'd not heard of that before. I may use it.
The physics is slightly broken unfortunately.
A radio signal may propogate without any metallic conductors, in air or in vaccum or "thin air" (think radar or GPS signals)
It is the characteristics of the dielectric (vaccum, air) that sets the speed of propogation.
The speed of light in air at 17C, 50% relative humidity and sea level pressure is about .031% less than it is in vaccum. That would be a reduction of 0.0036 inches to that 11.80285 inch long wire.
For my work I've always just used 300,000,000 m/s, which is accurate enough for any terestrial application.
If a radio signal is sent "over" some metallic conductors, you generally use two or more metal surfaces, such as two parallel wires or the inner and outer conductors of a coaxial cable.
As long as highly conductive metals (e.g. copper, silver, aluminum or gold) are used, the magnetic fields of an electromagnetic wave cannot penetrate a conductor, and the electric fields are confined to a very thin surface layer. The speed of electron propogation in a metallic conductor has little if any effect on the speed of the electromagnetic wave.
Typically the metal conductors are supported and separated by some kind of solid material (the dielectric) (teflon, ceramic, glass), it is the dielectric that sets the speed of propogation.
Trevor Carpenter
Forum Pro
Pleased I inspired someone else to give it a go
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