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Messages - heptagon

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EOS Bodies / Re: Canon EOS 7D Mark II Specifications Confirmed
« on: September 12, 2014, 09:35:12 AM »
If you shoot raw, then stick with ISO100 and be prepared to "underexpose" then fix in post.

well that's not good advice! :D

Care to explain why shooting at ISO100 but underexposed by 2 stops is worse than shooting at ISO400 on a Nikon 800/600 series?

Numbers are useful here.

You have two main sources of noise at low ISO:
1) Quantum noise
2) Readout noise

Quantum noise is due to the fact that photons behave like particles and if you on average expect 10000 photons in a pixel in reality you get sometimes more and sometimes less leading to a Poisson distribution around that average value. The quatum noise is the square root of the number of photons e.g. 100 for 10000 photons and 10 for 100 photons.

The readout noise is various electronic noise and depends on the amplification factor and other interference. With the new Sony sensors the readout noise is virtually the same on ISO 100 to ISO 6400 e.g. 5 electrons. With the canon sensors the readout noise is better for high ISO e.g. 3 electrons but worse at low ISO e.g. 30 electrons at ISO 100.

If you look at a bright pixel you get 10000 electrons from the photons +-100 electrons due to Poisson statistics (even a perfect sensor will get that). The S/N ratio is 100.

If you look at a dark pixel you get 100 electrons from photons and +-10 electrons from Poisson statistics. The S/N ratio is 10.

Now factor in the read noise.
- Bright pixel:
-- Canon: 100 and 30 => 104 total, S/N 96
-- Nikon: 100 and 5 => 100 total, S/N 100
- Not much difference.

- Dark pixel:
-- Canon: 10 and 30 => 32 total, S/N 3.1
-- Nikon: 10 and 5 =>11 total, S/N 9.1
- Almost a factor of 3!

If you do the same calculation at high ISO, the Canon sensor gets a little advantage.

From this we can conclude that BRIGHT pixels have the SAME QUALITY with a Canon and a Sony sensor.
But DARK pixels suffer from readout noise and here the Sony sensor is much better.

So if you do not underexpose or lift the shadows in your pictures, you will be OK with current Canon sensors.

EDIT: Use RMS for noise addition.

Third Party Manufacturers / Re: Zeiss Otus 85mm f/1.4 Reviews
« on: September 12, 2014, 08:00:19 AM »
DxOMark shows that this lens outresolves any of the current Canon fullframe sensors. It's been a long time since the last 1Ds...

EOS Bodies / Re: A Rundown of Canon at Photokina
« on: September 04, 2014, 10:36:29 AM »
4k for recording is not the same as 4k for playback.

Just compare mushy compressed 1080p with RAW 1080p. Having the option of using 4k for recording, then cropping (e.g. stabilization) and downscaling the compressed version of the video stream would be a very sensible option in many cases to produce high quality 1080p. So, no, it is not only a gimmick for people who know what they do with video.

EOS Bodies / Re: Plan B
« on: August 07, 2014, 07:26:13 AM »
i don´t care much about aps-c.

im only interested in the 7D MK2 because i want to see what canon does and if there will be an improvement in sensor technology.

Seeing the 7D mainly as a tele/action/sports camera probably something along the lines of a good phase detection AF + improved DualPixel technology. Maybe QuadPixels. Possibly initial focus acquired by the dedicated AF sensor, then handing off to Sensor focus to follow the objects and shoot at a high frame rate without moving the mirror. This would require a hybrid viewfinder.

So for sensor technology this doesn't mean necessarily mean very much improvement in regards to quality of low ISO still images. I wouldn't expect too much in this regard.

EOS Bodies / Re: Plan B
« on: August 07, 2014, 06:37:16 AM »
Continue making photos with the old gear.

EOS Bodies / Re: 7D now marked as DISCONTINUED at Amazon
« on: July 27, 2014, 08:01:23 AM »
Actually this means that Amazon is phasing out Cannons for Nikes due to the better dynamic rage and pixels revealed with the 810D.

And I thought heptagon meant Amazon was starting to sell cold war relics in place of American Civil War relics. ;)

Those Nikes you posted have quite some range. And they're big and white, too. Nice!

EOS Bodies / Re: 7D now marked as DISCONTINUED at Amazon
« on: July 27, 2014, 02:29:46 AM »
Actually this means that Amazon is phasing out Cannons for Nikes due to the better dynamic rage and pixels revealed with the 810D.

Lenses / Re: Tamron SP 150-600 f/5-6.3 VC Review
« on: January 04, 2014, 05:42:17 PM »
As the saying goes. Don't believe everything you see/hear on the internet.

So you are saying someone would just go on the internet and lie to the world?

Third Party Manufacturers / Re: New iPhone: Final Nail in the Coffin
« on: October 13, 2013, 09:09:33 AM »
Distance photography

Low-light photography

I'd like to add
Shallow DoF photography
What matters here is sensor size divided by f-stop number. You can only make good lenses up to about f/1 and it seems cheap lenses are stuck at around f/2. If you want to go shallower, you have to increase the sensor size.

Or to put it the other way around: A full frame DSLR with a f/5.6 lens could be replaced by a camera phone with an f/1 lens of shorter focal length and a chip of 8mm diagonal and produce THE EXACT SAME PICTURES (or even better because it has higher quantum efficiency and less read noise).

It seems to have some potent noise reduction algorithm.

Please take a picture of something with structure... maybe a wooden table lit by candlelight.

Lenses / Re: Recommend a 1.4x and 2x for my non-L lenses?
« on: September 01, 2013, 05:49:52 PM »
For which lens?

EOS Bodies / Re: 70D and Dxomark....
« on: August 30, 2013, 05:00:50 PM »
This forum feels like being caught in a loop, the same arguments repeated over and over again...

Reviews / Re: Which camera should I buy for a first timer
« on: August 11, 2013, 05:50:24 AM »
T2i and T3i have the same sensor. T4i adds in mediocre live view phase detection focusing.

T3i has video zoom (1:1 pixel video instead of line skipping) which some people like to use.
T3i has better phase detection AF compared to the T2i (can't remember exactly what but i think center point is same but outer focus points are better).

I don't think you'll need any feature the T4i provides. The 70D could prove worthwile but it's not out yet.

Magic lantern could be useful for learning because it offers you deeper control of the camera.

I'd get the T4i with the two kit lenses. They are not very good but you have every focal length 18-250mm covered and can add a decent prime to that (31mm would be 50mm full frame equivalent).

Lenses / Re: TS-E 90mm f/2.8 Replacement Info [CR1]
« on: August 10, 2013, 06:33:44 PM »
I've been playing around a bit with the TS-E 90 + 13+21+31mm Extension + 2x Extender and I got modestly sharp results at 5° tilt (more would have been unsharp) and could take a photo from a 10 degree angle. That was just enough to keep the lens (without hood) out of the reflection of a flat surface.

The reason for the low angle at the high tilt is in the short focusing distance (relative to the focal length of the lens, so a longer lens will not help here). When the Scheimpflug angle is 90° for infinity focus it's almost flat for a macro photo.

It would be great to take a 1:1 macro photo of a flat surface from a 45° angle but that would require much more tilt and the current lenses become very unsharp at large tilts when used with extension tubes.

So maybe a special lens design with a fixed large tilt would be possible but that would only be useful in a few macro scenarios. Still i'm curious what the macro tilt design is they may present.

Reviews / Re: Which camera should I buy for a first timer
« on: August 10, 2013, 12:44:45 PM »
go cheap.. it will show you what is important to you and then revisit in a year or two....

This! If it has manual focusing and manual exposure you can start to learn with any camera.

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