f5.6 vs f8 lenses

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Being new to LF....

How seriously should I consider buying f5.6 rather than f8 or f9 lenses? I know the f5.6 will be brighter and therefore easier to focus etc, but should I consider this a minor issue in choosing a lens or a major issue?

-- Chris Bitmead (chrisb@ans.com.au), August 08, 1998


Comparison of image circle, and weight are two factors to consider. Most f8 and f9 lenses are dimensionally smaller and significantly lighter, and have comperable coverages as the faster lenses.

G Claron 305, 381mm image circle, 67mm filter, $954.00. APO Symmar 300, 425mm image circle, 105mm filter, $2069.00.

Obviously you give up some brightness, and image circle, but the cost is half, new or used, and the weight and dimension gain of a slower lens is significant. When you start to try and shoe horn lenses on boards into a back pack or bag I think you will see what I mean.

Right now I am using a borrowed Fuji 300mm f9 on my 8X10 and I have only run out of coverage using extreme front rise, for 98% of the images I have shot the coverage was fine. It weighs about 1/4 of my Turner and Rich convertible of the same focal length, and takes up about 1/3 of the space.

Getting used to focusing a large format, with any lens takes some experience. With the f8 and f9 lenses it just takes a little more patience and technique. Obviously I consider the brightness issue to be minor, but I have a few years experience using the f8's and have adapted to thier peculiarities.

-- Marv Thompson (mthompson@clinton.net), August 08, 1998.

I think it depends a bit on the type of lens that you plan to purchase. For a long lens, such as a 360, the difference is not important. But for a wide angle, it can be critical.

For example, I have a Fuji 90 mm f5.6. Last summer, I used it in a rain forest in southeast Alaska. I wanted every stop of light that I had and more to see whether the image was initially focused where I wanted it. I could not stop the lens below about f22 without losing the corners to total blackness.

I pay a penalty for using this lens. It has an 82 mm front filter element. That's a lot of glass to haul around, but I know that there are times when I need it. However, you may not. A lot depends on the type of photography that you like to do. If you work in darker places, or need the extra movement possible with an f5.6 wide angle than with an f8, then go for the faster lens. Otherwise, the f8 should be fine.

Good luck,


-- Bruce M. Herman (bherman@arctic.net), August 11, 1998.

The added speed would only be used for focusing. I dont ever remember taking a shot faster than f16 or so, and usually more like f32. Try stopping the lens you have now to f8, and try some focusing. Thats what focusing an f8 is like.

-- Ron Shaw (shaw9@llnl.gov), August 11, 1998.

I use a 90 f8 SA, and replaced the original ground glass with one of those from Beattie. I think their claim of 2 f stop brightness increase is accurate, and its a lot lighter and cheaper than buying faster lens. Jeff

-- Jeff Thompson (poohfuff@aol.com), January 17, 1999.

Wide angle lenses have a hot spot. It doesn't matter who makes the lens. They all have a hot spot.

The fall off begins after about 70% of the coverage of the lens.

Faster lenses, I'll use ours as an example 4.5 Grandagon 236mm vs 6.8 Grandago 221mm, cover a larger circle than a slower version. Thus the fall off starts further out from the center. Thus there may be less need for the center filter if extreme movements or displacements are not used.

The faster lens is sharper and has better contrast. It also has less distortion.

The faster lens is larger, 82 vs 67mm filter and yes that means that if you need the center filter it costs more. And it is heavier 700 vs 460g.

The faster lens is 50% brighter on the ground glass so focusing is

-- bob salomon (bob@hpmarketingcorp.com), January 21, 1999.

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