View Full Version : f5.6 vs f8 lenses

Chris Bitmead
8-Aug-1998, 13:10
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 consid er this a minor issue in choosing a lens or a major issue?

8-Aug-1998, 14:36
Comparison of image circle, and weight are two factors to consider. Most f8 and f9 lenses are dimensionally smaller and significantly lighter, and have comperab le 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, n ew or used, and the weight and dimension gain of a slower lens is significant. W hen you start to try and shoe horn lenses on boards into a back pack or bag I th ink 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 cov erage was fine. It weighs about 1/4 of my Turner and Rich convertible of the sam e focal length, and takes up about 1/3 of the space.

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

Bruce M. Herman
11-Aug-1998, 04:37
I think it depends a bit on the type of lens that you plan to purchase. For a l ong 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 wh ether the image was initially focused where I wanted it. I could not stop the l ens 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. Tha t's a lot of glass to haul around, but I know that there are times when I need i t. However, you may not. A lot depends on the type of photography that you lik e 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, th e f8 should be fine.

Good luck,


Ron Shaw
11-Aug-1998, 12:59
The added speed would only be used for focusing. I dont ever remember taking a s hot 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.

Jeff hompson
18-Jan-1999, 00:26
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

Bob Salomon
21-Jan-1999, 06:28
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