PDA

View Full Version : Lens set based on field of view (FOV)?



pete22230
17-Mar-2018, 16:38
Hi everyone;
I'm a newbie to LF and thinking about lens sets. I currently have 2 lenses: a rodenstock 80mm f5.6 Grandagon (not a Grandagon-N) and a schneider symmar-s 180mm f5.6. I find I am looking at scenes from an "I want more/less field of view" (FOV) point of view rather than a "more/less focal length" (FL) point of view. I understand that there is a gross relationship between FOV and FL but depending on lens manufacturer/design it can be somewhat nebulous. Since I don't have full specs on the Grandagon I'm unsure of it's actual FOV but I would think it's 100+ degrees vs about 70 degrees for the Symmar-S. So on occasion I have found myself wishing for something between the 2. I also figure at some point I'll be getting a longer lens like a Nikkor M 300mm or maybe even a Nikkor T-ED 360mm. So what would you folks recommend for an in-between lens between my existing and that would have A) hopefully about an 85 degree FOV B) a modest lens hood diameter so filters are easy C) a bright lens say f5.6 D) a maximum image circle and E) light weight F) sharpness. Not asking for much am I!!!! Reading up on this I came across reference to a 120mm Schneider Super-Symmar HM that looked interesting but I'm sure there must be other choices. Any thoughts you might have would sure be appreciated.
Many thanks
Pete

Dan Fromm
17-Mar-2018, 18:03
Oh, dear. You're confusing the angle the film sees with the angle the lens covers. If the lens covers it, the angle the film sees is given by focal length.

On 4x5, an 80 mm lens (assuming it covers the format) will give a 61 degree vertical angle of view and a 74 degree horizontal angle of view. The diagonal angle of view will be 86 degrees. For a 180 mm lens, 30, 37 and 45.

Learn to do the calculations. Angle of view covered given focal length is, in pidgin Excel, 2*atan(degrees((circle/2)/focal length)). For 4x5 and vertical AOV, the circle is ~ 95 mm. Horizontal, 120 mm. Diagonal, 150 mm.

About lenses. Learn to use this site's resources. In particular, see http://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses

Bob Salomon
17-Mar-2018, 18:03
80mm?

The most common 3 lens set for 45 is the 90, 150, 210mm.

Corran
17-Mar-2018, 18:44
I'm sure you meant a 90mm Grandagon. There's no reason to consider lenses based on the FoV. For your 90 and 180, the obvious in-between is a 135mm, and the next step up probably a 300mm. Whether or not those work for you depends on your individual needs and seeing. Lately, my preference has been 90-150-240 (also 58).

More importantly as a self-proclaimed newbie is to go out and make photographs to determine what you need in terms of lenses.

Pere Casals
17-Mar-2018, 19:15
FOV


Hello Pete,

Here AOV is described: https://en.wikipedia.org/wiki/Angle_of_view

Here you have a calculator, you can also donload an App for your phone: https://www.scantips.com/lights/fieldofview.html

Angle of coverage: the circle of image of an LF les is usually large than the film, "allowing movements".

Here you have image circles and angle of coverage of some lenses: http://www.largeformatphotography.info/lenses/LF4x5in.html

Please note that when you focus a near subject with an LF camera you give bellows extension, the image grows a bit, and the Angle of View decreases a bit from what it was for a distant subject.

Regards

Oren Grad
17-Mar-2018, 22:26
I'm sure you meant a 90mm Grandagon.

FWIW, there was an 80mm Grandagon, early on. AFAIK it didn't survive into the Grandagon-N generation and it's not nearly so common as the various 90mm Grandagons, but there are some floating around out there. So the OP will have to confirm for us whether that was just a typo or whether he really does have the 80.

Corran
17-Mar-2018, 22:33
Huh, never heard of that, my bad. Perhaps it is that then.

Bob Salomon
18-Mar-2018, 01:49
FWIW, there was an 80mm Grandagon, early on. AFAIK it didn't survive into the Grandagon-N generation and it's not nearly so common as the various 90mm Grandagons, but there are some floating around out there. So the OP will have to confirm for us whether that was just a typo or whether he really does have the 80.

And, if he does, has he tried it to see how much it covers? That was a pretty old lens and was long discontinued when we became the Rodenstock distributor in the 80s.

Doremus Scudder
18-Mar-2018, 03:16
As Dan points out, you shouldn't confuse the angle of coverage (i.e., how big an image circle the lens projects) with the angle of view. This latter is directly related to focal length, so you really don't have to worry about it; just think in terms of focal length. This is somewhat easier for me than working out angles for all three parameters (width, height and diagonal).

Angle of coverage is important for choosing a lens with the coverage you need for whatever movements you commonly use (or to see if it covers a specific format at all), but it does not relate to the angle of view; rather different lens designs in the same focal length can have very different angles of coverage.

As for choosing lens sets. Many (me included) like a set that progresses in approx. 50%-focal-length intervals. Example: 90mm - (50% of 90 is 45; 90+45=) 135mm - (50% of 135 is 67.5; 135+67.5= 202.5) so a lens in the 200-210mm range is good here (my Ektar 203mm is very close :) ). The next entry in the series would be 300mm. This is what I carry most of the time in the field for general work.

But, you've got an 80mm and a 180mm already. So if you wanted to "split the difference" with the lenses you have already (assuming you do have the 80mm Grandagon, not the 90mm), then your 50% sequence would be: 80mm - 120mm - 180mm (- 270mm), etc. There are several good 125mm lenses (the Fujinons leap to mind) that would fit the bill quite well. Most ~120mm lenses are "wide-angle-of-coverage" designs (e.g., Super Angulon, Grandagon, SW). These are bigger, but have lots of coverage for 4x5. The type of work you want to do and the needed coverage will dictate which direction you want to go here. The 125mm-135mm Plasmat-designed lenses have less coverage, but are much smaller and lighter.

FWIW, I augment my 50%-increment set often depending on what I'm shooting. When working in cities, I add a 180mm and a 240mm and leave out the 300mm (entire kit: 90mm, 135mm, 180mm, 210mm, 240mm). I find this gives me more framing possibilities in places where choices for camera placement are limited. When working canyons in the SW, I'll add a 75mm and leave out the 300mm and go wider on the long end (entire kit: 75mm, 90mm, 135mm, 180mm). And even for general use, when I have room, I'll toss in a lens to fill in a gap that I think might need filling (often it's the 240mm Fujinon A that gets added, since it's so small). It's all highly personal and subject-specific.

For you, the obvious choice is something in the 120-135mm range. The decision should be based on the coverage you need vs. size/weight. Personally, I really like the 135mm focal length, but I like a lot of coverage. My choice here is the 135mm Wide-Field Ektar for the coverage. Your choice may be different. However, as far as quality goes, any of the lenses from the reputable manufacturers will be fine.

Hope this helps,

Doremus

Dan Fromm
18-Mar-2018, 06:38
Doremus, a set of lenses with 50% steps between focal lengths is interesting. Useful, too. But it isn't the only one.

I bought my first real camera, a Nikkormat FTn, in 1970. It came with a little pamphlet on the basics of photography. I learned a lot from the pamphlet and the exercises in it, still have it. Anyway, in it Nikon recommended a lens set with 100% steps. Double focal length upwards, halve it downwards. I took their advice, ended up with a kit that that had 24 mm, 55 mm, 105 mm and 200 mm lenses. I later added a 400 and (heresy!) a 35. My first longer lens was a disaster of a 1000, quickly sold off. Eventually I got a 700. When my kit was stolen I replaced the 35 with a 35-70 zoom. And there, more or less, is my 35 mm kit.

When I moved up in format to 2x3 I started with a normal lens, 101 mm, later added too many other lenses and ended up with more kit than I can carry and with focal lengths in relatively small steps. Too many choices. I've since slimmed down what I try to travel with to steps of around 50%. I see this as tidy but entirely arbitrary.

OP, my point here is there really aren't any hard and firm rules. Like it or not, you'll have to find your own way.

Pfsor
18-Mar-2018, 07:53
Once again, a simple portable viewing frame tells you precisely what FL you would prefer in your photographic situations. No need to ask anybody else about their taste and their vision - just you, your own aesthetics and your own decision. As simple as that.

Doremus Scudder
18-Mar-2018, 09:20
Doremus, a set of lenses with 50% steps between focal lengths is interesting. Useful, too. But it isn't the only one.

I bought my first real camera, a Nikkormat FTn, in 1970. It came with a little pamphlet on the basics of photography. I learned a lot from the pamphlet and the exercises in it, still have it. Anyway, in it Nikon recommended a lens set with 100% steps. Double focal length upwards, halve it downwards. I took their advice, ended up with a kit that that had 24 mm, 55 mm, 105 mm and 200 mm lenses. I later added a 400 and (heresy!) a 35. My first longer lens was a disaster of a 1000, quickly sold off. Eventually I got a 700. When my kit was stolen I replaced the 35 with a 35-70 zoom. And there, more or less, is my 35 mm kit.

When I moved up in format to 2x3 I started with a normal lens, 101 mm, later added too many other lenses and ended up with more kit than I can carry and with focal lengths in relatively small steps. Too many choices. I've since slimmed down what I try to travel with to steps of around 50%. I see this as tidy but entirely arbitrary.

OP, my point here is there really aren't any hard and firm rules. Like it or not, you'll have to find your own way.

Dan,

I wasn't trying to chisel anything in stone, just offering a suggestion that might work for the OP. I don't follow the 50%-spacing religiously, but it does seem to provide a fairly flexible kit for 4x5 in just four lenses. I don't think I could go with a 100% spacing for 4x5 though... 90mm - 180mm - 360mm would certainly be workable, but I seem to need intermediate focal lengths often. I know the danger of getting overloaded with focal lengths too, however. I try to keep it to four or five lenses, and lightweight ones at that, when in the field. I keep a bunch in the car when I'm road tripping and sometimes end up doing things like trading a 135mm for a 150mm just to use that extra bit of negative area. In the field, I'd just use the 135mm and crop when printing. For some reason, though, the 50% spacing works well enough so that when one lens is just a bit too long, I can go to the next longer and not feel like I am cropping too much to get the image I envisioned.

But, yes, there are no hard and fast rules.

Pfsor,

I like the viewing frame. I use a Zone VI viewing filter for sizing up potential shots. Choosing the correct focal length lens is easy once you get used to judging the distance between eye and frame. I rarely have to change lenses from the one I first choose.

Best,

Doremus

Bob Salomon
18-Mar-2018, 09:26
Dan,

I wasn't trying to chisel anything in stone, just offering a suggestion that might work for the OP. I don't follow the 50%-spacing religiously, but it does seem to provide a fairly flexible kit for 4x5 in just four lenses. I don't think I could go with a 100% spacing for 4x5 though... 90mm - 180mm - 360mm would certainly be workable, but I seem to need intermediate focal lengths often. I know the danger of getting overloaded with focal lengths too, however. I try to keep it to four or five lenses, and lightweight ones at that, when in the field. I keep a bunch in the car when I'm road tripping and sometimes end up doing things like trading a 135mm for a 150mm just to use that extra bit of negative area. In the field, I'd just use the 135mm and crop when printing. For some reason, though, the 50% spacing works well enough so that when one lens is just a bit too long, I can go to the next longer and not feel like I am cropping too much to get the image I envisioned.

But, yes, there are no hard and fast rules.

Best,

Doremus

One of the best ways is to look at the horizontal coverage, in degrees, of your favorite lenses on your usual format camera and then buy lenses with similar horizontal coverage for 45.

Or, look at the images you are currently making with your current lens and then decide if you need a little wider, little shorter, much wider or much longer and base your second lens decision on that. Then live with those two lenses and after shooting with them for a while make the same decision for your 3rd lens.
Again, after being the Linhof and Wista and Rodenstock distributor in the USA for multiple decades, the most common 3 lens set was the 90, 150 and 210mm. The 180 was the most common normal lens for 57.

Of course this was for new equipment.

pete22230
18-Mar-2018, 09:52
Hi again;
Thanks to everyone! Sounds like I have some screwed up fundamentals. I was basing a lot of my thinking on the published angle of coverage data from the manufacturers. So back to school. Dan thanks for the link and Corran/Oren yes I do have an 80mm. As near as I can determine it's early 70's but I might be wrong there. It's in great shape and came in a Linoff recessed board (don't know if it was originally a Linoff lens or just ended up there). My only complaint with it is that it's big with an 85mm front lens and a rear lens that you kind of have to wiggle inside the bellows. What really got me wondering was when I set up in the backyard with a compass and measured the angle of what I was seeing. It turned out that with the 80 I measured 75 degrees and with the 180 it was 30 degrees. I like the idea of a viewing frame although I've never seen one - tried a quick search and it seemed all I got was electronic picture frames from amazon and others - Doremus I'll check out the zone VI one - thanks.
I'm still a bit confused on the angle thing. Looking at Michael Davis "Specs for new large format 4x5 lenses" here on the site I see he has a Nikor SW 120mm listed with a 105degree angle of coverage just as the Rodenstock Grandagon-N 65mm. The difference seems to be that with the 120 you get 50% excess coverage. So for my purposes 120-135mm lenses like the Nikkor SW or Fuji SW with their big image circles give me the "in between" I'm looking for with the addition of lots of movement - Correct???
Once agin let me say thanks to everyone.
Pete

Pfsor
18-Mar-2018, 11:50
...

Pfsor,
I like the viewing frame. I use a Zone VI viewing filter for sizing up potential shots. Choosing the correct focal length lens is easy once you get used to judging the distance between eye and frame. I rarely have to change lenses from the one I first choose.
Best,
Doremus

I agree. Thanks to the viewing frame I always knew exactly what lens FL I needed and I never ever sold a lens once I bought it - I knew it will serve and it does.
Cheers.

ic-racer
18-Mar-2018, 13:24
So what would you folks recommend for an in-between lens

The field of view is inversely proportional to the focal length. So, double the focal length and the field of view is 1/2.

mdarnton
18-Mar-2018, 15:16
I'd say it depends on how much money you have. 50% jumps are good--90>135>200>300, and that's what I always aim for with a new system. If you have less money, 100%: 90>180m, and done. Some people have all the money in the world, and make every jump because they can: 65>75>90>115>135>150>180>210>240>300>360. It just depends on how fat your bank account is vs how willing you are to walk to a closer or farther spot and re-set your tripod, and how close you want to stay to the car. :-)

I think more to the point is to either have a regular spacing so that you can see what the change is going to be in your mind in advance, or to have favorite lenses for various jobs, if you prefer to think that way. Or a combination of that. I'm heavy around 300-380mm because I shoot a lot of 5x7 and 8x10 portraits, and that's a nice range for that. I have yet to use anything wider than 300mm on 8x10, so there's no need for that. On the other hand, for 35mm I'm completely happy with a 21mm and 50mm, and hardly ever use anything else because I don't like a heavy bag.

The bottom line is that there are a lot of ways to think of this problem. Which is best for you?

Greg
18-Mar-2018, 15:50
I agree. Thanks to the viewing frame I always knew exactly what lens FL I needed and I never ever sold a lens once I bought it - I knew it will serve and it does.
Cheers.

Here's my finder for framing (Linhof finder on a Hasselblad handle). Works for 4x5 and 8x10 with pretty much exact framing. Also use it for whole plate and 11x14 recognizing that the framing isn't exact but way good enough to frame the image. Added micro stickers for each of my lenses for each format.

Pfsor
19-Mar-2018, 04:55
I like the idea of a viewing frame although I've never seen one - tried a quick search and it seemed all I got was electronic picture frames from amazon and others - Doremus I'll check out the zone VI one - thanks.
Pete

You don't need to buy it - make one yourself. It's very easy and you can make it from a piece of cardboard or light plastic. Simply make a frame (like a passe-partout for pictures) of the same inner dimension as your film, put a string on its lower part, make knots on the string at the focal length you want to have and put that knot on the bone under your eye socket and see through the frame. You will have a very exact vision of your lens on the film. The viewing frame is light weight, easy to carry and you can have several of them for different film formats and FLs. My frame has written notes on it to remember the sequence of FLs on the string. I never leave the house without it when going to take pics. It's a great visually educational device that helps you to find the visual element you are after in the world around you.

pete22230
20-Mar-2018, 08:58
Hi Pfsor - that sounds like a great idea - why don't I ever think of these things?? I did some searching on the the Linoff and Horseman and was a bit taken aback by the $$$. Get another lens add another knot! I'm travelling at the moment but when I get home it's off to the shop.
Pete

Pfsor
20-Mar-2018, 12:06
Hi Pfsor - that sounds like a great idea - why don't I ever think of these things??
Pete

I agree, Pete. I often asked myself why this simple but very efficient device is not used more by LF photographers. You will be surprised how useful you will find it. It is the best method of pre-visualisation I know. Make the edge of the frame just wide enough and the picture you see through it jumps out at you immediately.

chassis
20-Mar-2018, 19:00
Agree with Doremus. For me it is about the subject and the desired way to represent it. I prefer strong perspective in architecture images, when (if) I can pull that off. This tends toward wider lenses such as 58mm-72mm. For portraits I like a traditional perspective, which for me falls in the range of 240mm-300mm for 4x5. In still life I like the 100mm-120mm perspective.

Field of view and angles of coverage are not how I think or work.