Peter - have you heard of any success with teleconverters?? I have a 2x converter that I was thinking of using with my Nikon 70-200 F2.8.
I'm wondering if internal reflections might be a problem.
DT
I tested a whole bunch of lenses by pointing them at the brightest mrecury vapour streetlight I could find (this replicates what you will see in the "diamond ring" phase pretty well...where the sun is still dammed bright! ) , and trying various exposures and F-stops.
Some camera lenses had horrible flares and reflections.
All I can say it test whatever you are hoping to use long before the eclipse.
I found simple optical systems worked the best...for example, there was not a whole lot of difference in the WO GT81 I tested and my way more expensive L-series Canon 500mm.
Also, don't run out of time ordering telescope stuff...relevant stocks often run out before a major celestial event.
P.S.
Attached an example of the flare you can get during an eclipse...
Perhaps just a good 300-500mm FL achromat (from binos), stopped down to F/11 0r 16 could be the good enough option...
However, personally, i wouldn't be annoyed by those flares, if they are not interfering (being on top of) with the important details of the image - it is obvious they are artefacts of the optical system, and therefore easily ignored (unless one wants a "PERFECT" image)
Peter - I presume that diamond ring shot would be considered overexposed?? Have you any other examples without overexposure?? Just wondering if the flare was better.
Peter - I presume that diamond ring shot would be considered overexposed?? Have you any other examples without overexposure?? Just wondering if the flare was better.
DT
The Diamond ring is a little tricky to capture as the photosphere is significantly brighter than the emerging corona.
The extent to which you can expoose for the corona will depend on the contrast/quality of the optics...in short there is no universal "right" exposure.
The attached image was taken just a second or two later, with a good result.
@joe: I'm wanting to make a composite of the corona at totality. I have a camera that doesn't support bracketing or computer control but I have bulb mode. Do you think timing various exposures manually within the two minutes of totality would work to make a HDR combine? I intent to use a canon remote and take the whole sequence by hand.
@joe: I'm wanting to make a composite of the corona at totality. I have a camera that doesn't support bracketing or computer control but I have bulb mode. Do you think timing various exposures manually within the two minutes of totality would work to make a HDR combine? I intent to use a canon remote and take the whole sequence by hand.
Easy. I manually adjusted corona exposures from 1/2000th through several seconds during the 2006 eclipse. Took lots of pictures...checking each. just kept at it. Many of the other photographers who were taking "automated" sequences had way more data...sadly for them 90% of it was unusable due a failed focus/exposure etc.
Yes thats the problem isn't it. If you rely on auto and it lets you down and you only find out after the event - that would be annoying.
Thanks for the info on setups. Some interesting data here.
I am thinking then my TEC110 at 613mm could be handy with a 40D that works so well on it. Then a 150 to 200mm lens on the D800E. Leave it on manual mode, focus and turn the autofocus off, and handle the ISO and exposure times manually. This is where being familiar with your camera will pay big dividends. Knowing where all the buttons are and how to adjust it quickly. Or use live view and you can see how its going to expose straight away.
Location: '34 South' Young Hilltops LGA, Australia
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Quote:
Originally Posted by multiweb
Great thread - following with a lot of interest.
@joe: I'm wanting to make a composite of the corona at totality. I have a camera that doesn't support bracketing or computer control but I have bulb mode. Do you think timing various exposures manually within the two minutes of totality would work to make a HDR combine? I intent to use a canon remote and take the whole sequence by hand.
Multiweb,
While Peter's statement is correct, I think he assumed you have a DSLR and didn't ask if your camera is a digital compact? Is it? Does it have manual mode with shutter speed control not bulb?
At f8 ISO 100 you need to shoot every shutter speed from the fastest available 1/4000 sec through to 2 to 4 seconds to do a full range composite. Only a small number of exposures are in the bulb range.
Tell us what camera you have and I sure either Peter or I can suggest something.
Easy. I manually adjusted corona exposures from 1/2000th through several seconds during the 2006 eclipse. Took lots of pictures...checking each. just kept at it. Many of the other photographers who were taking "automated" sequences had way more data...sadly for them 90% of it was unusable due a failed focus/exposure etc.
Cool - was that with *istD?
Quote:
Originally Posted by OzEclipse
Multiweb,
While Peter's statement is correct, I think he assumed you have a DSLR and didn't ask if your camera is a digital compact? Is it? Does it have manual mode with shutter speed control not bulb?
At f8 ISO 100 you need to shoot every shutter speed from the fastest available 1/4000 sec through to 2 to 4 seconds to do a full range composite. Only a small number of exposures are in the bulb range.
Tell us what camera you have and I sure either Peter or I can suggest something.
Joe
I have a SONY NEX-5 and a Pentax *istD. I intend to use the Pentax for a widefield timelapse on automatic exposure and have the NEX-5 with a 200mm lens on a polarie with a manual remote to capture the corona at totality.
I have a SONY NEX-5 and a Pentax *istD. I intend to use the Pentax for a widefield timelapse on automatic exposure and have the NEX-5 with a 200mm lens on a polarie with a manual remote to capture the corona at totality.[/QUOTE]
I suspect a time lapse on auto exposure will fail. That's because I find DSLRs don't auto expose to a wide enough exposure range for this sort of work.
For example from daylight to nightime transitions. I have done several now. I used aperture priority with an F2.8 lens and also set the camera to auto ISO with minimum and maximum ISO set.
This worked up to a certain point in the twilight and then it was inadequate at night as that would be ISO6400 and 30 seconds and no way will auto expose set the camera to do that. Aperture priority alone may not be enough and auto ISO is only a feature on a few cameras.
DSLRs are engineered mostly for daytime exposures and it shows in the settings available.
A test would be a time lapse from day to twilight levels matching expected light levels with the eclipse.
Thanks Greg. The SONY NEX-5 supports auto ISO in mode A, Aperture priority but that's the one I'll be using for the corona. Will check the Pentax *istD. I did a couple of transitions from day to night. What I did was stay next to the camera and bump the ISO when it got dark then later keyframe and interpolate the transitions in LR Timelapse.
Thanks Greg. The SONY NEX-5 supports auto ISO in mode A, Aperture priority but that's the one I'll be using for the corona. Will check the Pentax *istD. I did a couple of transitions from day to night. What I did was stay next to the camera and bump the ISO when it got dark then later keyframe and interpolate the transitions in LR Timelapse.
In my case though I use 30 second exposures and even at ISO50 that is too bright during daylight.
Perhaps I use shutter priority and manually adjust and shutter speed and keep the interval at 10 seconds
between images so I have enough time to do the adjustments.
Greg.
Last edited by gregbradley; 19-09-2012 at 02:43 PM.
In my case though I use 30 second exposures and even at ISO50 that is too bright during daylight.
Perhaps I use shutter priority and manually adjust and shutter speed and keep the interval at 10 seconds
between images so I have enough time to do the adjustments.
Greg.
My SONY only goes down to ISO200 minimum though. I have this PDF file from our last astro meeting that gives a lookup table for timing depending on what you want to image. They said to double up exposure time as the sun will be low so multiply all exposure times x2.
Just done a reassessment of my white light gear. I am going to go with my 300mm f2.8 with a 2x teleconverter on my D3. 600mm at f5.6 should produce nice results. My reasons were that my TSA would produce large images of the eclipse but cut off the extended parts of the corona. So I figure the 300 will produce the results I am after. Thoughts anyone?
Assuming I can get all the gear freighted up, I hope to run my FS-102 with 1.4x TC and Tak Epsilon 160 both with 5DMKIIs (1150mm f11 and 530mm f3.3). Might also think about renting a 5D MKIII with a 200mm lens and then be able to screw up three things at once..
Just done a reassessment of my white light gear. I am going to go with my 300mm f2.8 with a 2x teleconverter on my D3. 600mm at f5.6 should produce nice results. My reasons were that my TSA would produce large images of the eclipse but cut off the extended parts of the corona. So I figure the 300 will produce the results I am after. Thoughts anyone?
After my experience today with a 2x teleconverter, I'd go with the 300 prime.
The FS-60 will be 374mm focal length which will still only give a ~5mm sized sun on my chip - but definitely allows for a few solar radii.
Bound to be cloudy after I've invested in a new scope and portable mount, taken time of work, organised flights, hotel and hire car as well as spending spent hours testing software, writing a script and rehearsing...
Assuming I can get all the gear freighted up, I hope to run my FS-102 with 1.4x TC and Tak Epsilon 160 both with 5DMKIIs (1150mm f11 and 530mm f3.3). Might also think about renting a 5D MKIII with a 200mm lens and then be able to screw up three things at once..
Phil
Ever shot an eclipse before Phil? I can tell you it is a manic few minutes. Three units is going to have you racing.
Quote:
Originally Posted by DavidTrap
After my experience today with a 2x teleconverter, I'd go with the 300 prime.
The FS-60 will be 374mm focal length which will still only give a ~5mm sized sun on my chip - but definitely allows for a few solar radii.
Bound to be cloudy after I've invested in a new scope and portable mount, taken time of work, organised flights, hotel and hire car as well as spending spent hours testing software, writing a script and rehearsing...
DT
I will have to go with manual focus or buy a Nikon TC 2x because the sigma one I have causes the focus to hunt on my prime. I vaguely remember that the 2x is not really suited for this lens, but a 600mm focal length will give a quite large image on the sensor. What went on today? Sorry have not kept up.
You can bank on cloud in Cairns. Lived there for 18 months from '88 to '90 and I am expecting cloud on the day, but being part of the experience and our last two eclipses were cloud affected I see cloud as being part of the excitement factor.
As for software I am going with preset exposures and bracketting. I cannot be bothered with hooking that part of my kit up to yet another computer. Remember the main thing is to enjoy being in the shadow of the moon and seeing the corona.
