Sigma 150-600mm for Deep Sky Widefield ?

[smr 331]

Hi all,

I am looking to upgrade and have decided on an HEQ5 Pro Mount but I am wondering which refractor to buy and whether it is indeed necessary for me to buy one. The reason I ask is because I have a 150mm-600mm f5-6.3 Sigma camera lens and from reading around this sounds like an ideal focal length range for widefield deep sky imaging which is what I am interested in - objects like M42 and the Rosette / Lagoon Nebula etc.

The thing is I can't find many images related to Deep sky with this lens, which maybe for a reason - so is there a reason why an SW Evostar 80ED scope would be better than the Sigma lens? If the lens is not going to be sufficiently good enough for imaging compared to a refractor like the Evostar could you please tell me why this is? I am willing to sell the lens as I am not as interested in wildlife or motorsport photography anymore and am more interested in landscapes for daytime photography and really enjoy astro photography, so I don't really have much need for it - but if it's going to be adequate for Deep sky imaging then obviously I'd keep it - I just have a feeling that I would be better off with a refractor but I don't the knowledge to discern why that would be so.

 

Thanks for any advice.

[SteveNickolls 1,132]

Hi smr,

Thanks for posting. I can't help you with any knowledge of the lens nor telescope but there are two good reviews here of lenses I can direct you to-

https://www.lenstip.com/index.html?test=obiektywu&test_ob=434

https://www.lenstip.com/417.11-Lens_review-Sigma_S_150-600_mm_f_5-6.3_DG_OS_HSM_Summary.html

I hope someone with direct knowledge will be able to more fully answer you.

The lens will give you an option to image at different FL's and quicker optics than the telescope and you'll need to factor in a flattener/reducer into the overall cost of the telescope for imaging. How do the telescope and lens compare cost-wise? Can you get a good second hand lens to help keep the price down or is price no object for you?

Good luck with your future imaging.

Cheers,
Steve

[HowardHopkinson 98]

Though I haven't used the exact lens you're thinking of buying, I have used a Sigma 120-400 mm F4.5-5.6 zoom lens with a Canon 60D APS-C camera and gotten some pretty useful results. See below for an example image.

 

[tooth_dr 4,704]

 

1 hour ago, smr said:

I am wondering which refractor to buy and whether it is indeed necessary for me to buy one.

 

The most logical thing to do is to get the HEQ5 mount and try the lens for imaging since you already own it. Then if it doesn’t meet your expectations get an ED80. Or am I missing something?

[RichM63 4,670]

9 minutes ago, tooth_dr said:

 

 

The most logical thing to do is to get the HEQ5 mount and try the lens for imaging since you already own it. Then if it doesn’t meet your expectations get an ED80. Or am I missing something?

Nope Toothy, you are not missing anything, that was exactly my first reaction. (ps any news on T/Brush)

I do have a 150-600 Sport but have not tried deep sky, Moon is good on static tripod so give it a go at least.

Rich

[tooth_dr 4,704]

4 minutes ago, RichM63 said:

Nope Toothy, you are not missing anything, that was exactly my first reaction. (ps any news on T/Brush)

I do have a 150-600 Sport but have not tried deep sky, Moon is good on static tripod so give it a go at least.

Rich

I haven’t forgotten Rich! This year I promise

[wxsatuser 4,889]

2 hours ago, smr said:

Hi all,

I am looking to upgrade and have decided on an HEQ5 Pro Mount but I am wondering which refractor to buy and whether it is indeed necessary for me to buy one. The reason I ask is because I have a 150mm-600mm f5-6.3 Sigma camera lens and from reading around this sounds like an ideal focal length range for widefield deep sky imaging which is what I am interested in - objects like M42 and the Rosette / Lagoon Nebula etc.

The thing is I can't find many images related to Deep sky with this lens, which maybe for a reason - so is there a reason why an SW Evostar 80ED scope would be better than the Sigma lens? If the lens is not going to be sufficiently good enough for imaging compared to a refractor like the Evostar could you please tell me why this is? I am willing to sell the lens as I am not as interested in wildlife or motorsport photography anymore and am more interested in landscapes for daytime photography and really enjoy astro photography, so I don't really have much need for it - but if it's going to be adequate for Deep sky imaging then obviously I'd keep it - I just have a feeling that I would be better off with a refractor but I don't the knowledge to discern why that would be so.

 

Thanks for any advice.

It may be worth a try first.
That huge 90mm front group with 2 low dispersion elements and a near fluorite element down the other end could do the business.
I do have one but never tried it for AP.

Many nebulae are quite big and the shorter focal lengths like 150 and 200mm will cover whole nebula with ease, unless you like mosaics.

 

[smr 331]

Thanks for the replies, indeed the logical thing I suppose would be to try it but then I was thinking if there is a good reason why I shouldn't then I wouldn't have to waste a few imaging sessions trying to see what the results are like. I have imaged the moon with it before

Moon by Joel Spencer, on Flickr

Edited August 28, 2018 by smr

[smr 331]

22 minutes ago, wxsatuser said:

It may be worth a try first.
That huge 90mm front group with 2 low dispersion elements and a near fluorite element down the other end could do the business.
I do have one but never tried it for AP.

Many nebulae are quite big and the shorter focal lengths like 150 and 200mm will cover whole nebula with ease, unless you like mosaics.

 

I had to crop in a lot on M42 though, at 250mm (with my 55-250mm lens)

[Alien 13 5,893]

I would keep the lens, cant imagine any two element frac like an ED80 could match it.

Alan

[celestron8g8 281]

How old is your Sigma lens ? I have an older version Sigma 135-400 APO lens and it has terrible lens creep so i never use it for astroimaging . Also Sigma lens use to have reputation of being a somewhat soft focus which is also my lens problem . I bought it for astro and wildlife imaging but got big dissappointments     . So if your going to astroimage i suggest either a different lens , using a creep band on big lens 400mm and larger or even better use a prime telephoto lens or best use a refractor of equivelant needs . 

[smr 331]

10 minutes ago, celestron8g8 said:

How old is your Sigma lens ? I have an older version Sigma 135-400 APO lens and it has terrible lens creep so i never use it for astroimaging . Also Sigma lens use to have reputation of being a somewhat soft focus which is also my lens problem . I bought it for astro and wildlife imaging but got big dissappointments     . So if your going to astroimage i suggest either a different lens , using a creep band on big lens 400mm and larger or even better use a prime telephoto lens or best use a refractor of equivelant needs . 

Not very old, bought in 2016. It has a focal length switch to avoid lens creep. 

[tooth_dr 4,704]

41 minutes ago, smr said:

Thanks for the replies, indeed the logical thing I suppose would be to try it but then I was thinking if there is a good reason why I shouldn't then I wouldn't have to waste a few imaging sessions trying to see what the results are like. I have imaged the moon with it before

Moon by Joel Spencer, on Flickr

That is a nice shot.

I wouldn’t worry about wasting imaging sessions. If you haven’t done deep sky imaging before there will be a lot more to go wrong than just lens choice, be prepared for just about anything to go wrong 

[smr 331]

11 hours ago, tooth_dr said:

That is a nice shot.

I wouldn’t worry about wasting imaging sessions. If you haven’t done deep sky imaging before there will be a lot more to go wrong than just lens choice, be prepared for just about anything to go wrong 

Thanks. I have imaged before but not on an advanced level (ie. guiding, PHD etc.) but guiding is something I want to do and if I'm going to be using longer focal lengths in the region of 500-600mm I'd need to be really. Which would be easier from what I gather with a scope as you can just attach a guidescope on the tube rings. With a Camera lens it's not as easy as that in that they don't come with tube rings.

[tooth_dr 4,704]

59 minutes ago, smr said:

Thanks. I have imaged before but not on an advanced level (ie. guiding, PHD etc.) but guiding is something I want to do and if I'm going to be using longer focal lengths in the region of 500-600mm I'd need to be really. Which would be easier from what I gather with a scope as you can just attach a guidescope on the tube rings. With a Camera lens it's not as easy as that in that they don't come with tube rings.

There are a few ways to do it even with a camera and lens.  But this moves the goalposts on your original question.

 

 

[Z3roCool 284]

I got the NEQ6 and was in the same boat. Tried a friends zoom lens (Cannot remember exactly what it was now). Got fairly decent results. Found we had to tape the ring to stop it from slipping (Maybe just his lens). Was getting 3-4 mins unguided at about 400mm, over that and 4 mins was pushing it (Slight oval stars). I have used my Prime Lens (400) which I have got some pretty good results with (For me). I have held off buying an ED80 for 2 reasons, lens gets me good results at the moment when I am still learning and money! As I think you have already decided, give it a go and then go onto a scope later down the line.

[Space Oddities 286]

I have read many times that these lenses are a bit soft for DSO, even though they are good for wildlife and sports. But that should not stop you from trying! Lens performance is subjective, after all.

I could only find a couple examples on Astrobin, but that's the Contemporary version (which I think differs from the Sports version): https://www.astrobin.com/gear/61400/sigma-150-600-mm-contemporary/

There is also the Tamron, not the same brand of course, but that will give you an idea of what can be achieved with similar specs: https://www.astrobin.com/gear/36000/tamron-tamron-150-600mm-f5-63-di-vc-usd/

Also, when I want to find examples pictures with a given lens or scope, I usually type e.g. "astrobin canon 400mm" in my search engine. Astrobin is good for referencing the gear used, and there are always a lot of sample pictures to analyse! 

[rigradio 64]

This is the Tamron version -> Andromeda

You will find Tamron vs AT65EDQ images on that page also. 

[Lukeliu 0]

I happened to see this discussion thread, because I also have this lens (C version), I also used it to take the DSO, these are the finished images I took, for your reference.( these image shoot @ 600mm with mod-Nikon D610 and BackyardNikon, iOptron Cem25p, PHD2 Guiding)

Andromeda Galaxy

Rosette Nebula

M45

Horsehead Nebula

M42

all images exposure 10(or more)X3 mins with dither and stack with DSS

( came from Taiwan, wrote these use google translate)

Edited March 30 by Lukeliu