Pentax 67ii lenses - astrophotography

Hi, I have a Pentax 67ii and 45mm , 75mm shift , 90 mm -180 mm lens . I came across the time exposure mode and want to try astrophotography. which of the lenses would be suitable?

how do I determine exposure?

 

thanks and have a nice one.

Sanjay

Hi Sanjay

 

I don't have that camera myself but there's a very talented astrophotographer over on Cloudynights.com, James Cormier, who uses that camera. He also has an impressive Flickr stream.

 

This is the film astrophoto forum:

 

Film Astrophotography - Cloudy Nights

 

Good luck

Philip

 

Hi, I have a Pentax 67ii and 45mm , 75mm shift , 90 mm -180 mm lens . I came across the time exposure mode and want to try astrophotography. which of the lenses would be suitable?

how do I determine exposure?

 

thanks and have a nice one.

Sanjay

I've done a fair bit of astrophotography and I think what you first need to do is ask yourself what sort of astrophotography are you interested in doing? Also, how familliar are you with astronomy? Astrophotography does require some level of knowledge of astronomy, after all. Your 45mm will be good for wide field stuff, like a shot of the milky way galaxy. Often including background elements in the photo, such as trees or rocky prominences, can be effective. Some star clusters may benefit from moderate telephoto focal lengths. Other, moe deep sky objects, will often require the focal lengh you get from a rather large telescope. So, it all depends on what you're trying to accomplish. Thus, I recommend that the first thing you do is read up on the subject. The internet is full of sites with all sorts of info, and of course there are books. After getting somewhat of a handle on the subject, you'll be in a much better position as to what you'd like to accomplish with your outfit. And finally, if you're serious, be prepared to spend money. Yeah, you can probably find cheap DIY workaounds on YouTube, but they may or may not even be worth the trouble. At any rate, you'll be better off from the knowledge you've gained and what you can expect to accomplish with your outfit. Edited April 13, 2017 by mwmcbroom

HI, thanks for the reply. I am not looking at spending too much money. Considering the time exposure feature of Pentax 67ii , I wanted to see if I could take astronomical photos. shooting slides and negatives.

Hi,

I've been shooting the night sky for over 50 years. Years ago shooting with 6x7 was considered the ultimate way to go and the Pentax lenses were very good for it. But if your serious about getting the best results film is no longer the answer. There are very few films available in 120 color that are sensitive into the near IR region. The new CMOS sensors can be modified to pick up IR light (where the majority of nebulosity is), have no reciprocity failure and will capture more light in 30 seconds than a 10 minute exposure on film. As far as lenses go, the best lenses for astrophotography are APO, ED, or L. The long Nikkor ED and Canon L (Leica & Zeiss APO's) being the best. It is important that all colors focus at the same point when the lens is used wide open. You probably know all of this. Your 6x7 is very large and heavy which will introduce balancing and tracking issues. Do some reading and rethink it. If your talking about simple photos of the milky way near mountains that's completely different than capturing close ups of nebula or distant galaxies. Your 6x7 and Pentax lenses will work fine for the Milky Way, but you still need to have it on a aligned mount that is tracking.

This is one of the better links on astrophotography:

Catching the Light - Astrophotography by Jerry Lodriguss

I have not updated my work for quite some time, some images were with film but most using a 8mp Canon. There are serious amateurs out there who put my work to shame with lesser equipment...and they are not using film.

Astrophotography by Rick_Jack

 

If you want to try your 6x7, Kodak E200 if it's available has the best red sensitivity. What are you mounting your camera to for the tracking?

Great results in your gallery, Rick!

 

You have a shot "NGC 7000 - First Light" - with good red nebula response from a Nikon D750. Was it a modified camera?

Sanjay,

 

As Rick says, film is no longer the first choice for shooting faint objects through a telephoto lens or telescope, but it can give nice wide-field results, especially with a tracking mount.

 

One of the easiest and best ways to use medium format film for astrophotography is in shooting longish (many-minute) star-trails. They are difficult to shoot "cleanly" on digital, without having either gaps between the typical stacked moderate exposures (30-60 sec) or an accumulation of long exposure dark-noise, and the colours in the stars can be better with film. You also do not need a special tracking mount.

thanks for the reply. I think I will try the star trails. how do I determine the exposure and account for the reciprocity factor? can I do this without tracking mount?

I also have canon 35mm eos bodies with wide angle 17-40 lens and longest being 400mm f5.6 and 1.4 teleextender.

On medium format, was thinking of Slide film like velvia.

Star trails are what you naturally get without a tracking mount. Just use a normal tripod.

 

Exposure depends on the usual variables of f-stop, film ISO and exposure time...but the imponderable is sky brightness, varying greatly due to factors such as light pollution, haze, and moonlight, which makes it difficult to give any set rule. Reciprocity failure is less of a factor than this...it is fairly mild with modern slide films like Velvia (it is generally worse with negative film).

 

So you'll have to experiment and bracket. In a dark rural sky, try ISO 100, f/4 or f/5.6, 20 or 30 minutes. Stop down more for brighter skies or for longer exposures. Some people shoot for several hours at f/11 - you lose the fainter stars with the smaller aperture, but the trails are much longer. If you point at the Pole Star, you get circular arcs of circumpolar trails. Elsewhere in the sky, you get more gradually curved arcs. Use a wideangle or normal lens for best effect.

If you get tired of star trails and wish to capture something more challenging, you will need some form of tracking device for exposures longer than a few seconds (500/FL). The inexpensive Option "Sky Tracker" would be marginal for the Pentax 67, with a weight limit of just over 2 pounds. Luminous-Landscape recommends a heavy duty German mount for medium format photograph, especially for deep space objects. Optron and others make suitable mounts. While large and heavy, they are not necessarily super expensive (~ US$1500 or so). Most can be used with a computer to locate objects by ascension and declination coordinates.

 

My objective, this summer, is to get some "starry landscapes" in which the foreground plays an important role. That means traveling at lest 60 miles from Chicago, where the sky is always pink (and you need someone to watch your back).

 

Digital sensors are essentially free of reciprocity failure. Their limitations include thermal noise, which can be handled on an amateur basis using blank shots and combining multiple exposures. The professionals do all of this, plus using liquid nitrogen to cool their sensors.

Edited May 31, 2017 by Ed_Ingold

Hi,

I apologize I should of kept my thoughts closer to what you intend to do and your existing equipment.

Your camera and lenses are fine. How dark are your skies? In an ideal location you shouldn't be able to see your hand in front of your face. I live in the suburbs and my film will fog (background gray) in as little as a 30 second exposure depending on the f-stop and ISO.

Velvia is too slow for astrophotography and not as sensitive in the red spectrum as Ektachrome 200.

As mentioned by others, sky trails are easy. Take many and bracket your exposures. If you want the stars to remain as points you will need to track for exposure times over 15 seconds. A device like this is probably the best way to go:

SkyTracker Camera Mount with Polar Scope - Black

The summer sky is upon us and the best part of the Milky Way will be due south during July-August.

Experience through trial and error is the best teacher.

Best of luck.

Rick

I agree that some sort of tracker is a necessity for exposure times of any length at all unless star trails are the goal. But it is still possible to capture some interesting stuff with just a telephoto lens and a sturdy tripod. This shot was taken with a 10.1mp Canon XS DSLR and a Century Precision Optics 650mm f/6.8 manual iris telephoto lens. I don't recall the shutter speed anymore or the ISO, but it probably wasn't any higher than 400 because that camera just doesn't handle high ISOs very well. The file's EXIF data seems to have been lost, so I can't determine shutter speeds or ISO unfortunately. This was shot from my backyard, well inside the suburbs of Houston, so the sky was pretty well light-polluted. Fortunately, for planetary photography, light pollution is not that great of a hindrance. Yep, Jupiter with its four Galilean moons, Io, Europa, Ganymede, and Callisto.

 

http://michaelmcbroom.com/images/jupiterandmoons.jpg

Edited June 2, 2017 by mwmcbroom