suggest manual lens for milky way

Started Jun 21, 2013 | Discussions
kcire
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suggest manual lens for milky way
Jun 21, 2013

I just captured a milky way photo with NEX-5N + 16mm + VCL-ECU1.

I did it but that's very difficult to find infinity focus even using focus peaking in very dark situation.

I think next time I want to use manual lens which has distance mark.

I'm thinking about Samyang 14/2.8, is it good to NEX?

Please suggest the other manual lens which:

- ultra wide (12-20mm)

- small body (not bulky)

- has fix and large aperture (f/2.8)

- has distance mark

thanks

Sony Alpha NEX-5N
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nevercat
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Re: suggest manual lens for milky way
In reply to kcire, Jun 21, 2013

First: Beautifull picture! Very nice!

Second Focussing on the stars  is very difficult, it does not matter what lens you use. The focuscale on a MF lens is not accurate, differences in temperature will change the focus setting you need (even when focus is right, when temperatures are dropping you may have to refocus. So focussing iwill always be difficult...

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Astrophotographer 10
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Re: suggest manual lens for milky way
In reply to nevercat, Jun 21, 2013

Lens wide open, ISO to maximum (I think its 12800) turn focus peaking off- its only distracting. Point to the brightest star, use magnified live view and use the LCD. You should be able to see a bright enough star like that. That is what I use with my Nex 6. I sometimes use the EVF but the LCD is fine.

Alternatively point towards a distant light source if there is one nearby and focus on that. Or focus during the day and tape the focus ring so it doesn't move or put a bit of tape where infinity focus is so you simply line up the tape marks at night.

That lens looks good wideopen. That is unusual. Most have coma or bad chromatic aberration so you would be better off persisting with that lens.

Besides another lens won't help you if its also F2.8.

Greg.

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kcire
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Re: suggest manual lens for milky way
In reply to Astrophotographer 10, Jun 21, 2013

i'm using f/2.8,  iso 1600 / 3200 and 20-30 seconds

the peaking focus and mf assist helps a lot at the first 30 minutes, but after I change focus to a FG / POI, then the problem begins. It can't infinity again for the rest time. is it because low temperature?

i don't understand why e-mount lens focus ring has neverending turn.

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nevercat
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Re: suggest manual lens for milky way
In reply to kcire, Jun 21, 2013

kcire wrote:

i'm using f/2.8, iso 1600 / 3200 and 20-30 seconds

the peaking focus and mf assist helps a lot at the first 30 minutes, but after I change focus to a FG / POI, then the problem begins. It can't infinity again for the rest time. is it because low temperature?

It should not be for the temp, as long as you'r not in very cold conditions that is, but check the lens fpr fog...

i don't understand why e-mount lens focus ring has neverending turn.

That has to do with the focus by wire, the MF is not directly coupled with the focus system, but it command the focus motor in the lens, but it is not coupled, sa it does not turns when you auto focus the camera. So lets say you MF to infinity, Swithch the camera off, then AF the camera to very close by and swithch to MF you should not be able to focus to infinity again as your ring is at the end stop.

It would be nice if they found a way that you can still feel a stop at infinity...

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Astrophotographer 10
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Re: suggest manual lens for milky way
In reply to kcire, Jun 21, 2013

I don't quite understand this. You would normally shoot in M mode (manual) once focused there is no need to focus again usually. Not sure what you mean by changing AF modes.

You need to keep the camera lens a bit warmer than the ambient air in cold weather otherwise it will fog up. You can do this as simply by putting the lens in your pocket for a while.

I use a bit of insulation wrapped around the lens before I go outside and that prevents heat loss and delays fogging up. You can also get chemical heat pads and wrap them on the lens and put some insulation on 2nd if fogging is really bad.

Greg.

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C.Eaton
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Re: suggest manual lens for milky way
In reply to kcire, Jun 21, 2013

Great sky shot 

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mike winslow
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Re: suggest manual lens for milky way
In reply to Astrophotographer 10, Jun 21, 2013

It's more likely operator, or firmware and not fog Greg.  I think he's using an E-lens and not an M42.

On his original question - I've had some pleasant wide fields on a very inexpensive Vivitar S1 28mm 2.5 on an m42 mount for under 1 minute subs, untracked.

With a lens this small, it's the smallest of nudge between in and out of focus eg FWHM ~<2 to FWHM 10.

He needs to focus with spot metering and have the lens in MF, not DMF. LENS comps OFF. ISO as low as you can go, since the camera processor is going to try to stretch the frame.  There is allot the camera does to the frame, even before the RAW gets written which appears to contradict the common mythos

Turn off noise reduction I think, and capture your own Darks and bias frames.  shoot multiple exposures and stack. There is some freeware out there, but I use MaximDL and photoshop.  process in 16 bits as long as you can for better SNR (and IQ).

Personally, I'm very tempted to hang this camera on my TAK-FSQ/Temma combination, but my situation prohibits this for now..  This Exmor sensor looks better than my peltier cooled Ex-HAD in allot of ways.

I've been collecting million year old photons for 13 years now.

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wictred
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Re: suggest manual lens for milky way
In reply to kcire, Jun 21, 2013

great shot.

you can also try using a laser pointer for focusing

 wictred's gear list:wictred's gear list
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teaberry
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Are you guys using GEMs for these shots to avoid "trailing"?
In reply to kcire, Jun 22, 2013

I was out in southeast asia with a beautiful dark night and when doing 30sec exposure pics, I start to see stars trailing. I notice your pics minimize that so I was wondering if you're using a German Equatorial Mount or some other device? I appreciate the advise as I am very interested in getting into Astrophotography.

Also, any recommendations on a budget telescope to mount the NEX (NEX-7) for under $500? I will have a separate budget for a GEM of course. Thank you.

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mike winslow
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Re: Are you guys using GEMs for these shots to avoid "trailing"?
In reply to teaberry, Jun 22, 2013

a simple single axis motorized mount .. trying to think of the name, but something like OM-1.. it comes in a tabletop and tripod. something less than $100

It's not very accurate, but will be much better than nothing.  The last time that I was out with a lens on the astro camera, I had the guider on my FSQ,  on a temma mount, so going several minutes was easy.

A single axis will track the rotation of the earth, and even with an eyeballed polar alignment, you should see a dramatic reduction in trailing, especially in such a wide field.  You'll need to refine as you go..  pretty much get the north star centered in your FOV.

The other thing that you can do, which is free, is shoot shorter subs, then stack them.  There is freeware out there, but I havent tried them, and I'm not sure if they handle our image sizes well..  Google image stacking if you're not familiar, but it also gives you a better signal to noise ratio over a single image.  You might also want to think about doing dark frame subtraction, but I think that the camera does this with the long exposure NR under settings.

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Astrophotographer 10
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Re: Are you guys using GEMs for these shots to avoid "trailing"?
In reply to mike winslow, Jun 22, 2013

The rule for star trailing exposure length is 600/focal length gives max exposure in seconds before star trailing is objectionable.

Perhaps even 500/focal length. So that gives you around 35-45 seconds for a 14mm focal length (full frame equivalent).

As most cameras only allow a max of 30 second shots before you have to start mucking around with add-ons (why do they do that - they spend huge amounts to provide some obscure menu item and a basic function of the camera is overlooked for year and years) it tends to mean 30 seconds it tops.

So 30 seconds ISO3200 or 6400 at F2.8 if the lens can handle it (most can't) will give you a bright exposure. Long expsoure noise reduction on a lot of the time (unless its cold and it tends not to be needed then).

This image using a 16mm shows that lens is useful. Samyang 8mm F2.8 fisheye works well for this type of shot as well.

So you must have been using a longer focal length lens like a 50mm which will show star trailing after about 10 seconds of exposure.

Vixen Polarie is the most popular portable mount. Its tiny, its well made, it $400, its easy to use and it works well. It runs off batteries. It will hold above its rated capacity. It can handle a D800E and 14-24m lens which is heavy. Just make sure you have a pair of pliers to tighten up the tightening screws snug enough.

Orion ED 80 is a popular scope that is fantastic bang for your buck. Quite a high performer for a low price. Polarie would not handle that though. You'd need a GEM. Skyatcher EQ 6 is popular.

Greg.

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teaberry
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Thank you Greg and Mike, here is a sample of where I think some sort of EM would have helped...
In reply to Astrophotographer 10, Jun 23, 2013

I had no idea what I was doing, but it was such a beautiful night in Southeast Asia one night, I decided to take my cheap Slingshot tripod, remote, and the 16mm with the wide-angle converter. I'm sure you will cringe at the equipment, but I do think it could have produced better results if I had a more stable tripod and/or equatorial mount?

Any advise is appreciated. It was a 55sec exposure.

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teaberry
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Another pic. What could I have done to get sharper round stars?
In reply to Astrophotographer 10, Jun 23, 2013

This is another shot that I would have loved to have more round and sharper stars.

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RustierOne
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Re: suggest manual lens for milky way
In reply to kcire, Jun 26, 2013

kcire wrote:

I just captured a milky way photo with NEX-5N + 16mm + VCL-ECU1.

I did it but that's very difficult to find infinity focus even using focus peaking in very dark situation.

I think next time I want to use manual lens which has distance mark.

I'm thinking about Samyang 14/2.8, is it good to NEX?

Please suggest the other manual lens which:

- ultra wide (12-20mm)

- small body (not bulky)

- has fix and large aperture (f/2.8)

- has distance mark

thanks

Nice Milky Way image - thanks for sharing!

As for a good manual lens for Milky Way I have two suggestions depending on how much you want to capture in a single image. First the E-mount Samyang 8mm f/2.8 works great for nearly whole-sky shots. Here's an example:

Sony NEX-5N w/ Samyang 8mm f/2.8, ISO 1600, 2-1/2 minute exposure, tracked

Now if you want to shoot much more narrow views, I recommend the M42 mount Mamiya-Sekor 55mm, f/1.4. It is from a 1970's Mamiya-Sekor film camera and can be gotten quite inexpensively. Stopped down to f/2.8 or f/3.5, it's sharp in the corners, which is rare for many lenses. Here's a couple of single shots of part of the Milky Way:

Sony NEX-5N w/ Mamiya-Sekor 55mm f/1.4 @ f/2.8, 2 minute exposure, tracked, M24 & Sagittarius

Sony NEX-5N w/ Mamiya-Sekor 55mm f/1.4 @ f/2.8, ISO 1600, 2-1/2 minute exposure, tracked, North American Nebula

Single shots with this lens can be assembled into nice Milky Way panoramas using the (free) Microsoft ICE program (Image Composite Editor). Here's an example:

Mamiya Sekor 55mm f/1.4 @ f/2.8, composited from scanned film exposures, Milky Way from Cygnus to Scutum

Both lenses are full manual with distance scale. Infinity focus seems to be right on.

-
Best Regards,
Russ

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kcire
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Re: suggest manual lens for milky way
In reply to RustierOne, Jun 26, 2013

@rustier: nice milky way too

@greg: i'm only use the camera, lens and tripod with 400/focal length rule. with vcl-ecu1 attached it became 12mm so 400/12 = 33.33 seconds max

i don't know about GEMs... what's that?

@all : thanks for suggestion.

basically i love my 16mm and vcl-ecu1, the only cons are neverending focus ring and no distance mark.

probably i'll consider samyang, but don't know which one better between 8mm or 14mm

the price is quite high too...

and this is me... lighting by flashlight

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lesnapanda
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Re: suggest manual lens for milky way
In reply to kcire, Jun 26, 2013

Thats an amazing photo!

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Sony Alpha NEX-6 Sony E 16mm F2.8 Pancake Sony E 50mm F1.8 OSS Sigma 30mm F2.8 EX DN
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Astrophotographer 10
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Re: Another pic. What could I have done to get sharper round stars?
In reply to teaberry, Jun 26, 2013

Very nice. ISO 1600 or 3200 would have gotten a much brighter image and consequently allowed a shorter exposure time. ISO200 is too low and ISO400 also too low for this type of work. Its all in the ISO3200 - 6400 x 30 seconds at 14-21mm focal length type shot untracked on a tripod with long exposure noise reduction on or ISO1600-3200 on a tracked mount.

GEM= german equatorial mount - a type of telescope mount that has 2 axes that rotate to match earth's rotation and can point anywhere in the sky.

Greg.

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Pal2012
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Re: suggest manual lens for milky way
In reply to kcire, Jun 26, 2013

Thanks for sharing! And good question, though I am sure the Zeiss 24 would do very well maybe even the SEL35 but probably too narrow.

This was with the SEL16 / Nex5n and dirty air..

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kcire
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Re: suggest manual lens for milky way
In reply to Pal2012, Jun 29, 2013

Thanks for sharing! And good question, though I am sure the Zeiss 24 would do very well maybe even the SEL35 but probably too narrow.

This was with the SEL16 / Nex5n and dirty air..

Nice photo...
Would be more amazing if the sky is clear.

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