Just wondering ~ Would extension tubes be of any benefit in astro photography

[JBW]

Last night I got a decent shot of M4. I'm wondering if extension tubes would be of any benefit? The reason I ask is that as I understand extension tubes they increase magnification.
Brian

[rpcrowe]

I am lost because I don't know what the "M4" you are referring to is.

Basically extension tubes can increase magnification in close-up or macro photography by allowing the camera/lens to focus closer than you would be able without the tubes. The tubes are simply that, hollow tubes which increase the distance of the lens from the sensor. The better models of these tubes have electrical connections which can control focus and exposure. In fact, I bought a set for less that $15 USD which had these connections. But, you get what you pay for. The build quality of these tubes was atrocious.

OTOH Tele Extenders or tele converters (TC) fit between the lens and the camera to increase the focal length of the lens with which you are shooting. These can be used at any distance but, not all cameras/lenses are compatible with extenders. I know that when I was investigating the use of a TC with my 90mm Tamron Macro on a Canon 7D, I learned that it was not physically possible to use a Canon 1,4x TC with that lens unless I placed an extension tube between the rear of the lens and the TC. This would have given me a 126mm focal length lens with very close focusing capability but, would have eliminated using the combination at infinity. I "think" they other brand teleconverters may be compatible with the 90mm Tamron Macro and still retain infinity focus.

However, you might be better off to get zoom with a long end around 300mm. A used lens of that type would be in line with cost of a decent TC...

[JBW]

I am lost because I don't know what the "M4" you are referring to is.

Basically extension tubes can increase magnification in close-up or macro photography by allowing the camera/lens to focus closer than you would be able without the tubes. The tubes are simply that, hollow tubes which increase the distance of the lens from the sensor. The better models of these tubes have electrical connections which can control focus and exposure. In fact, I bought a set for less that $15 USD which had these connections. But, you get what you pay for. The build quality of these tubes was atrocious.

OTOH Tele Extenders or tele converters (TC) fit between the lens and the camera to increase the focal length of the lens with which you are shooting. These can be used at any distance but, not all cameras/lenses are compatible with extenders. I know that when I was investigating the use of a TC with my 90mm Tamron Macro on a Canon 7D, I learned that it was not physically possible to use a Canon 1,4x TC with that lens unless I placed an extension tube between the rear of the lens and the TC. This would have given me a 126mm focal length lens with very close focusing capability but, would have eliminated using the combination at infinity. I "think" they other brand teleconverters may be compatible with the 90mm Tamron Macro and still retain infinity focus.

However, you might be better off to get zoom with a long end around 300mm. A used lens of that type would be in line with cost of a decent TC...

Whoops bad me. M4 is a globular cluster in the constellation Scorpius. I am using my Tamron for DSLR astrophotography, This shot taken last night shows M4 as a faint fuzzy that forms a triangle with the two bright stars in the center of the shot.

[Mike Buckley]

Brian,

Richard's statement shown below is everything you need to know. Your issue with astrophotography is not that your subject is too close to be able to focus using lenses you already have. So, the answer to your question is: No, extension tubes won't help.

Basically extension tubes can increase magnification in close-up or macro photography by allowing the camera/lens to focus closer than you would be able without the tubes.

[JBW]

Brian,

Richard's statement shown below is everything you need to know. Your issue with astrophotography is not that your subject is too close to be able to focus using lenses you already have. So, the answer to your question is: No, extension tubes won't help.

that answers that question

[george013]

that answers that question

With extension tubes you can't focus at infinity anymore.
At infinity your focal distance and image distance are equal. But both are laying in front of the sensor.
A tele converter is changing the focal length, it's an added lens to the existing lens.
Interesting your turn to the sky.


George

[JBW]

With extension tubes you can't focus at infinity anymore.
At infinity your focal distance and image distance are equal. But both are laying in front of the sensor.
A tele converter is changing the focal length, it's an added lens to the existing lens.
Interesting your turn to the sky.


George

I was a visual observer for years. I had dark skies and few neighbors. Never really considered astro photography because of the cost. The a while back I ran across DSLR astro photography. Minimal cost. Maximum enjoyment. And I get a kick out of using my macro set-up for deep space.

[george013]

I was a visual observer for years. I had dark skies and few neighbors. Never really considered astro photography because of the cost. The a while back I ran across DSLR astro photography. Minimal cost. Maximum enjoyment. And I get a kick out of using my macro set-up for deep space.

For many years I had a caravan in the country side. Also clear sky, fascinating to watch the stars.
Have you considered long exposures or photo stacking, making the movement of the stars visible? Should be possible with your gear.

George

[William W]

The only useful means that I can think of . . .

Last night I got a decent shot of M4 [a globular cluster in the constellation Scorpius]. I'm wondering if extension tubes would be of any benefit? The reason I ask is that as I understand extension tubes they increase magnification.

An Extension Tube, cannot be not used to increase the magnification, (as already explained) but an Extension Tube might be useful (probably necessary to physically aborted it) and then for it to be used as a connection to attach a telescope to the camera.

WW

[JBW]

The only useful means that I can think of . . .



An Extension Tube, cannot be not used to increase the magnification, (as already explained) but an Extension Tube might be useful (probably necessary to physically aborted it) and then for it to be used as a connection to attach a telescope to the camera.

WW

That would be a T-mount.

[DanK]

George's answer is the key, not Richard and Mike's. Yes, extension tubes allow you to focus closer, but one can also use them at distances much greater than MFD, and at any distance at which they allow focus, they will produce more magnification than the naked lens because they are spreading a smaller image circle on the sensor. I do this routinely when hunting bugs. I usually use a tube to allow me to get closer than the lens's MWD and thereby to get greater magnification, but I often end up pulling back and getting well under 1:1. The key is that tubes make infinity focus impossible.

A telextender would work, as Richard points out. However, most do create some loss of optical quality. Before I bought a longer lens, I often used a Canon 1.4x II with my 70-200. It produced acceptable images, but looking closely, one could see some degradation when compared with the lens alone.

[rpcrowe]

My neighbor is very into astro photography as an adjunct of his astronomy hobby. I sold him one of my 7D cameras when I purchased the 7D2.

He has a very complicate telescope and gets some rather nice image. However, in viewing his images, I realized that I have little, if any, interest in that facet of photography which is good for me because, it certainly save me money.

I really don't have enough hours in a day to work with my rescue dogs and to do my other types of photography.

OTOH: I might try some relatively simple sky photography using my Canon SX50-HS bridge camera which can get me out to 1200 mm equivalent.

[Mike Buckley]

With extension tubes you can't focus at infinity anymore.

I didn't realize that. Is there a situation when using extension tubes that we would want to focus on infinity if doing so would be possible?

[george013]

I didn't realize that. Is there a situation when using extension tubes that we would want to focus on infinity if doing so would be possible?

As far as I can think of: no. When using an extension tube you're moving the F-point away from the sensor. So your image plane will be before the sensor at infinity.

George

[JBW]

My neighbor is very into astro photography as an adjunct of his astronomy hobby. I sold him one of my 7D cameras when I purchased the 7D2.

He has a very complicate telescope and gets some rather nice image. However, in viewing his images, I realized that I have little, if any, interest in that facet of photography which is good for me because, it certainly save me money.

I really don't have enough hours in a day to work with my rescue dogs and to do my other types of photography.

OTOH: I might try some relatively simple sky photography using my Canon SX50-HS bridge camera which can get me out to 1200 mm equivalent.

You're right astro photography gets really expensive really easily. Bridges can get you superb moon shots. Any macro lens can get you interesting wide angle star shots. The kicker is that pp is insanely critical.

[Manfred M]

Any macro lens can get you interesting wide angle star shots.

Huh?

Sorry John, that statement does not make any sense to me.

Macro lenses are designed for closeup photography and astrophotography has got to be the complete opposite of that, as your subject is very far away. Yes, you can use a macro lens for other types of photography; so I can see focal length being the determining factor here, not the macro aspect.

[rpcrowe]

Brian,

I have become a great fan of Kindle books. There is a multitude of titles available on a great variety of subjects.

I did a search on Amazon.com for "Kindle Books about photography" and this one popped up. When I looked at it, I immediately thought of you.
https://www.amazon.com/Photography-N...1PHREJWYZZ11YN

I love history and have purchased two great kindle books that list history related books available free... Just search Amazon or Google using "Free Kindle Books" as the search parameters.

I am able to get all the reading that I need or want at either a very low cost or totally free. The Kindle books have some great advantages over printed books:

1. My better half doesn't mind me collecting Kindle books because these books don't take up space and collect dust
2. I can adjust the Chromebook so that it is easy for these old and tired eyes to read. Larger type and a black background with brighter type does the job for me.

The books are immediately delivered to my Chromebook which is set up with a Kindle App. I would expect that would be an advantage to you in not having to worry about shipping...

Here is a selection of Kindle books I found on Google by using "Free Kindle Books about photography" as my search parameters:
https://www.slrlounge.com/5-free-ebo...eid=983c58ad91

I also use my Chromebook for viewing "HOW TO" YouTube videos. I can have the Chromebook right there as I am working on a project. When viewing a YouTube Photoshop video, I can have Photoshop open on my desktop computer and follow along the instructions using the Chrome book right next to the desktop monitor. Works really great that way...

FINALLY... Here is a selection of Kindle books on astrophotography...
https://www.amazon.com/s/ref=nb_sb_s...trophotography

[Cogito]

Brian, perfectly o.k.for a B&W but perhaps lacking a bit in content? A bit surprised that you used a 90mm lens instead of your bridge Fuji which extends to 550+ mm! But to return to a previous post of yours, maybe it's time to invest in something like a Minolta 100-300 mm lens? I know you've intimated an interest in another bridge camera, but the one you have isn't too bad and another decent (very) lens for your Sony wouldn't go amiss.

[JBW]

Brian,

I have become a great fan of Kindle books. There is a multitude of titles available on a great variety of subjects.

I did a search on Amazon.com for "Kindle Books about photography" and this one popped up. When I looked at it, I immediately thought of you.
https://www.amazon.com/Photography-N...1PHREJWYZZ11YN

I love history and have purchased two great kindle books that list history related books available free... Just search Amazon or Google using "Free Kindle Books" as the search parameters.

I am able to get all the reading that I need or want at either a very low cost or totally free. The Kindle books have some great advantages over printed books:

1. My better half doesn't mind me collecting Kindle books because these books don't take up space and collect dust
2. I can adjust the Chromebook so that it is easy for these old and tired eyes to read. Larger type and a black background with brighter type does the job for me.

The books are immediately delivered to my Chromebook which is set up with a Kindle App. I would expect that would be an advantage to you in not having to worry about shipping...

Here is a selection of Kindle books I found on Google by using "Free Kindle Books about photography" as my search parameters:
https://www.slrlounge.com/5-free-ebo...eid=983c58ad91

I also use my Chromebook for viewing "HOW TO" YouTube videos. I can have the Chromebook right there as I am working on a project. When viewing a YouTube Photoshop video, I can have Photoshop open on my desktop computer and follow along the instructions using the Chrome book right next to the desktop monitor. Works really great that way...

FINALLY... Here is a selection of Kindle books on astrophotography...
https://www.amazon.com/s/ref=nb_sb_s...trophotography

I shall look into this.

[JBW]

Brian, perfectly o.k.for a B&W but perhaps lacking a bit in content? A bit surprised that you used a 90mm lens instead of your bridge Fuji which extends to 550+ mm! But to return to a previous post of yours, maybe it's time to invest in something like a Minolta 100-300 mm lens? I know you've intimated an interest in another bridge camera, but the one you have isn't too bad and another decent (very) lens for your Sony wouldn't go amiss.

If my wife reads this she'll put a curse on you. But I have been looking into various lenses