Just for Fun No C&C will be given: Ice moon

[Ivan Garcia]

Suffering form insomnia today. Must be the full moon.

Canon EOS 1D MKIV EF 500 f/4L stacked a 1.4 and a 2X convertors. To my surprise, the Camera Auto focused with no problems whatsoever.
Images where imported to CS4 for Levels, Curves, size reduction and sharpening.

 

[Asher Kelman]

Ivan,

This is a pretty good picture. I always think this kind of detail is amazing. Those lines are an enigma.

It's interesting that you could use the x1.4 and x2 and get good focusing. There's such a prejudice against adding the x2.0 for anything serious.

I wonder f you might try this on a street sign.

Asher

 

[Ivan Garcia]

Hi Asher .
Thank you for the kind words. I don't think the image is particularly god. No to my usual standards anyway. The image below is more on par to what I would normally allow other people to see.

I was simply restless in bed, and though; if I am not going to get any sleep, I might as well take a picture of the moon . I took this with my new MKIV and like I said, I was surprised the camera focused. That was the reason I posted it (on an impulse).

Anyway, thank you for taking the time to look and comment on the image, I'll be sure to give the stacked set up a more comprehensive test.
Below a picture of the moon I took in 2008.

 

[Bart_van_der_Wolf]

Hi Ivan,

I took this with my new MKIV and like I said, I was surprised the camera focused.

Good shot, Ivan.

The surprise presumably being that a stacked 1.4x and a 2x extender costs 3 stops which, combined with an f/4 lens, amounts to f/11 when used wide open. AF usually stops with most cameras at apertures narrower than f/8. The EOS 1 series can stretch that limit a bit for the central AF point only, if there is enough contradt to focus on.

The moon itself is bright enough, it's frontally lit by the sun. That's why a common rule of thumb for shooting a full moon is: Sunny 11. That means that at ISO 100 and f/11, one needs an exposure time that's the reciprocal of the ISO value, so 1/100th of a second. To reduce the chance of motion blur, or atmosperic turbulence, one can boost the ISO and shutterspeed in sync.

When the moon phase is not full, one needs to use a relatively slower exposure time, or open up the aperture a bit (if possible), to compensate for the more oblique lighting angle of the moon's surface.

Ivan probably knows all that, but I thought it might help others who are less familiar with shooting the moon.

Cheers,
Bart

 

[Asher Kelman]

Good shot, Ivan.

The surprise presumably being that a stacked 1.4x and a 2x extender costs 3 stops which, combined with an f/4 lens, amounts to f/11 when used wide open. AF usually stops with most cameras at apertures narrower than f/8. The EOS 1 series can stretch that limit a bit for the central AF point only, if there is enough contradt to focus on.

Bart,

Thanks for the reminder on the f stop limit for most cameras in focussing. I though also that the x2 extender was also somehow of lesser quality than the x1.4 and degrade the picture. Getting to the f stop, do you think that the picture detail is harmed by that aperture given the pixel size of the 1D Mark IV? Also is there any difference in diffraction disturbance by f stop achieved by just the actual size of the aperture or is the image protected because the light was decreased by the physics has not changed as the light goes through a larger aperture than we would normally get at f11 woth the same lens and no extender?

Asher

 

[Asher Kelman]

Good shot, Ivan.

The surprise presumably being that a stacked 1.4x and a 2x extender costs 3 stops which, combined with an f/4 lens, amounts to f/11 when used wide open. AF usually stops with most cameras at apertures narrower than f/8. The EOS 1 series can stretch that limit a bit for the central AF point only, if there is enough contradt to focus on.

Bart,

Thanks for the reminder on the f stop limit for most cameras in focussing. I though also that the x2 extender was also somehow of lesser quality than the x1.4 and degrade the picture. Getting to the f stop, do you think that the picture detail is harmed by that aperture given the pixel size of the 1D Mark IV? Also is there any difference in diffraction disturbance by f stop achieved by just the actual size of the aperture or is the image protected because the light was decreased by the physics has not changed as the light goes through a larger aperture than we would normally get at f11 with the same lens and no extender?

Asher

 

[Ivan Garcia]

Good shot, Ivan.

The surprise presumably being that a stacked 1.4x and a 2x extender costs 3 stops which, combined with an f/4 lens, amounts to f/11 when used wide open. AF usually stops with most cameras at apertures narrower than f/8. The EOS 1 series can stretch that limit a bit for the central AF point only, if there is enough contradt to focus on.

The moon itself is bright enough, it's frontally lit by the sun. That's why a common rule of thumb for shooting a full moon is: Sunny 11. That means that at ISO 100 and f/11, one needs an exposure time that's the reciprocal of the ISO value, so 1/100th of a second. To reduce the chance of motion blur, or atmosperic turbulence, one can boost the ISO and shutterspeed in sync.

[snip]

Cheers,
Bart

Indeed, it also surprised me that the camera did not recognize the 1.4 as the aperture and lens focal length was identified as F/8 and 1000mm. ( 2X on lens and 1.4X on camera)

You are also right in that the AF with a stacked combo only works with very high contrast subjects. I tried the rig this afternoon and it just hunted back and forth.

The second image was taken with my 1DS MK3, 500mm, and 2X. I don't normally follow the usual rules for moon shooting (ISO, aperture, Shutter speed sync). I tend to under expose by 1/2 to a full stop and bring the shadows up a bit in CS4 with the shadow highlight tool.

Asher, I have been using the 2X converter with mixed success. I find the combination needs high contrast ratios to produce reasonably sharp images. I would not recommend using a 2X converter in low contrast situations.

As for diffraction, I know that as a rule of thumb, with my 1DsMKIII is best not to go beyond F/11. (it varies with some lenses) I have not tested the MKIV with all my lenses as yet.