alpenglow

<p>The new Fuji GF670 would be awesome for street photos. Might consider that as well.</p>

<p>Jon Paul,</p>

<p>I usually try and expose as long as possible (to record as many stars as possible), and still keep those stars looking like points, rather than trails. The length of that exposure will depend on the focal length of the lens... the more you magnify, the shorter your exposure because you will be manifying star movement. Therefore, the wider angles will allow longer exposures. A simple equation to determine where that cut-off occurs is as follows:</p>

<p>For 4x5 format, Take you lens' focal length, and divide it into 1800 to equal the number of <em>seconds</em> you can expose and keep the stars looking like points. So for example, if you're using a 150mm lens, 1800 divided by 150 equals 12 seconds. If using a 90mm lens, then 1800 divided by 90 equals 20 seconds. And if using a 75mm lens, then 1800 divided by 75 equals 24 seconds. This serves as a "ballpark" estimate, and there are variables that will affect the equation like what part of the sky you're pointed at, and what latitude you're at. But it works pretty well. You'll probably be able to go a bit on the longer side of exposure and still get very acceptable results... so maybe 28 seconds rather than 24 seconds for a 75mm lens. Of course, if you want startrails, then expose as long as you desire. Due to the generally slower speeds of large format lenses, I would try and use wider lenses to get as much exposure time as possible (which you'll want anyway to cover more sky and landscape foreground).</p>

<p>Happy hunting,<br />Mike</p>

<p>Amazing image Michael! I'll send you a personal e-mail so we don't hijack this thread.</p>

<p>Mike</p>

<p>Thanks for the additional info and examples Kelly. Those are some beautiful shots of Orion. I wonder though how well a digital camera (or any battery operated camera) will do in -40 degrees for 8 hours... actually I already know since I've tried ;-) Not long at all.</p>

<p>A 75mm lens on 4x5 is equivelent to about 25mm on a 35mm system or <strong>50mm</strong> on a 6x7. I use a 50mm on my RB. A "normal" lens is already starting to get too long for the aurora. The aurora will many times cover 180 degrees (or more) of the sky, and you'll want to capture as much of it, (along with some landscape) as possible. Plus, you can only expose for about 12 seconds with a normal lens before to start to see star trails, and you can expose 2 or 3 times this long with a wide angle. You'll be truly <strong>amazed</strong> at how many more stars will record with a 30 second exposure verses a 12 second exposure. And... by using 120 film, or 4x5 film at ISO 200 or 400, it will be grainless compared to the noise or grain you'll see with 800 or 1600 ISO. I've made 40 inch enlargements (traditionally printed from the original negative), and they are as smooth as silk.</p>

<p>Regardless Jon Paul of which equipment you choose, get out there and enjoy the sky!! Solar activity seems to be picking up, so the aurora should soon grace our skies once again.</p>

<p>Best,<br>

Mike</p>

<p>The aero ektar , while fast, is too long for aurora work. You'll want a wide angle to capture lots of sky, for some foreground landscape for composition, and to extend the length of exposures before stars begin to trail. That's why I suggested the Biogon at 75mm on 4x5 it would be perfect. And while not as fast as the ektar, it can truly be shot wide open, and with 400 ISO... that's plenty fast enough. Back when I was using 35mm for aurora photography, I would many times use 100 ISO, and it was plenty fast enough at f/2.8. It really isn't necessary to "freeze" the aurora, so you don't need supper fast exposures. I actually try to expose as long as possible before the stars begin to noticeably trail, so that you record as many stars as possible. With a wide angle focal length, this tends to be between 20 and 30 seconds.</p>

<p>But if you can't afford the Biogon, (wish I could ;-) again, I really think you would be well served with medium format. It's what I use all the time... Mamiya 645 systems and the RB67. The lenses are plenty fast enough, even at f/4 and 5.6 with 400 ISO. There also will be no reciprocity failure issues... and use print film rather than chromes to give an extra margin of error. I ocassionally push the processing to get a bit more contrast. My reccomendation is to stay away from digital. All digital cameras are super battery dependant, and with the cold temps you'll be working in, batteries get zapped very fast. Besides, if you're after quality enlargements, no digital can touch medium format film for resolution... period.</p>

<p>You can check out my "nocturnes" folder for some aurora photography examples... all film and both 35mm and medium format.</p>

<p>Best of luck!!<br>

Mike</p>

<p>I researched the same question Jon Paul, and came to the conclusion that you're better off using 120 film and medium format equipment, since there are more emulsion choices in 120, and the lenses are faster. Unless you have deep enough pockets for a Biogon... which I don't :-) But if you do, you can shoot the Biogon wide open. And since it's also a wide angle it works especially well for aurora compositions and gives you about 30 second exposures without showing startrails.</p>

<p>Mike</p>

<p>I have the F-2 and F-1X that I use to carry around my Mamiya medium format gear, and I find that the F-2 is still too small. But I love the F-1X. My vote is for the F-1X... you will fill it up... believe me :-)</p>

<p>Mike</p>

<p>No reason to be depresed A Bruce, since your dream is perfectly doable. So I'm not sure why your research was so inaccurate. I think it's because people just arn't creative enough with their thinking, or they get so focused on only doing something one way, (like trying to mate a large format camera directly to a telescope), that they come to the quick and wrong conclusion that it's "not possible". No reason at all why you can't mount an 8x10 or 4x5 camera to an equatorial drive... using a vacuume back film holder (to keep the film flat over the course of the long exposure), use wider focal lengths, and then proceed to make very long exposures of the constellations. Been done before, many... many times.</p>

<p>Mike</p>

<p>Peter,</p>

<p>As others have pointed out, using digital would certainly be <strong>easier</strong> , but this is not your only or even best option. Shooting the moon with large format is certainly doable, and will not be an excercise in futility by any means... I have done this myself. But, you will need to do it via eyepiece projection. If done right, the quality of the image on 4x5 film will be superior to anything you'll be able to get with digital SLRs or 35mm film (assuming you're using a quality telescope and eyepiece). But if you don't want to make the extra effort to get the best image possible, then certainly digital is an option.</p>

<p>Mike</p>

<p>Also... because the Mamiya's image circle will have much larger coverage than the 36mm CCD, you won't have any issues with coma or abberation... you'll be able to shoot wide open no problem.</p>

<p>Mike</p>

<p>Nicolas,</p>

<p>You might consider making your own barndoor tracker rather than getting an equatorial mount. A well made barndoor does an excellent job using the wider focal lengths and for exposures up to about 45 min.</p>

<p>Mike</p>

<p>Yep... eyepiece projection through a telescope is the only way to go.</p>

<p>Mike</p>

<p>Scott,</p>

<p>The Mamiya 200mm APO f/2.8 would be perfect for that application. Not exactly cheap though.</p>

<p>Mike</p>

<p>I would look at the Mamiya 645 system options. The Pro and ProTL versions are wonderful, but the 1000s camera is also great at a much reduced price. I have all of the above (in addition to other medium format systems), and can attest to the quality and bang for the buck.</p>

<p>Mike</p>

<p>Synthesize all that has been said above and you have your answer. Holgas are a blast and are wonderful to help train your eye and to force you to be creative. They are capable of producing truly beautiful images in the right hands. But, because of their limitations, they are not a good choice for a first medium format camera. Get a camera that has greater features and quality lenses, and then maybe also get a Holga (for $25.00), in addition, to help you explore your creative side.</p>

<p>Mike</p>

<p>A used Mamiya 6 matches your needs, except maybe the cost factor.</p>

<p>Mike</p>

Images that remind you of how fortunate we are to live on this jewel of a

planet.<div></div>

<p>I don't know about the filter brands you mention. But I agree that good quality filters are a wise investment (Hoya and Tiffen make great, affordable filters).</p>

<p>There are only a few filters that will be of real use to you. By far, the one filter to have with you all of the time is a polarizer. This filter is a must and is useful for either digital or film cameras. If you are using digital, most of the filter effects can be done in post processing. If you are shooting with film and you're interested in B&W, then you'll want to get a red #25 and yellow #15 for contrast variations. ND filters are also useful if you want to experiment with long exposure imaging. And graduated ND filters to balance exposure in contrasty scenes are also handy on ocassion, but you'll want to get square - adjustable filters for this application (like the Cokin series).</p>

<p>But again, before you get anything else, look into a good polarizer.</p>

<p>Mike</p>

<p>My experience with dr5 has been excellent. Especially using the Efke IR 820c film. You've got to try this IR emulsion in dr5... really beautiful chromes!</p>

<p>Mike</p>

<p>Check out the classified section of APUG (<a href="http://www.apug.org">www.apug.org</a>) Lots of LF guys there looking for good equipment.</p>

<p>Mike</p>