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01-17-2016, 03:07 AM   #226
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QuoteOriginally posted by Digitalis Quote
I don't know of anyone who uses AF for 1:1 macro work, stacking is more common with 2:1 and greater magnifications where there is never enough DOF.
I don't use autofocus for close-up work at present (I hesitate to say macro, because most of my subjects are at less than 1:1), but I do use stacking when I want an entire flower, for example, in focus. I keep debating with myself whether or not to buy Helicon focus. If I do, I would certainly use auto-focus then for stacking on subjects as large as flowers or military models (another hobby of mine) as it's not possible to get front to back sharpness even at apertures of f11.

01-17-2016, 05:26 AM   #227
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QuoteOriginally posted by Cynog Ap Brychan Quote
it's not possible to get front to back sharpness even at apertures of f11
scared to stop down more than f/16? wuss.
01-17-2016, 06:23 AM   #228
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QuoteOriginally posted by Digitalis Quote
scared to stop down more than f/16? wuss.
lol! f16 is for large format! I like to work where my lenses are most comfortable, which is usually F5.6 or f8. I'm not brave enough to venture into the murky waters of f22 or 32 yet!
01-17-2016, 06:53 AM   #229
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F16 leave a lot of space for diffraction already on aps-c. But the discussion about AF for focus stacking is pointless as you do use manual focus for this kind of work and you move the camera.

01-17-2016, 07:12 AM   #230
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QuoteOriginally posted by Glorfindelrb Quote
But the discussion about AF for focus stacking is pointless as you do use manual focus for this kind of work and you move the camera.
Maybe you don't us auto-focus: I maybe wrong, but I thought that Helicon could use the auto-focus on cameras to take a series of shots at predetermined intervals for focus stacking.
01-17-2016, 08:46 AM   #231
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QuoteOriginally posted by Cynog Ap Brychan Quote
lol! f16 is for large format!
f/16 is nothing, try f/64. In fact a vast majority of 4X5 and 8X10 lenses perform optimally at f/16, some at f/22
01-17-2016, 09:13 AM   #232
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QuoteOriginally posted by Digitalis Quote
f/16 is nothing, try f/64. In fact a vast majority of 4X5 and 8X10 lenses perform optimally at f/16, some at f/22
th

That's true. For 8x10, f64 might still has a large physics aperture similar to f8 or f5.6 in aps-c.

Last edited by starjedi; 01-17-2016 at 09:21 AM.
01-17-2016, 10:35 AM - 1 Like   #233
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QuoteOriginally posted by Digitalis Quote
f/16 is nothing, try f/64. In fact a vast majority of 4X5 and 8X10 lenses perform optimally at f/16, some at f/22
I know: I have a 5x4 camera, though it hasn't seen the light of day for a long time (anyone want to buy a VGC Toyo monorail camera?). Back in the old days (and no, I wasn't around then) the F64 club used to look down their noses in disdain at milksops who used a larger aperture, in much the same way as I look down on present-day MILCsops who use an EVF instead of a proper viewfinder!

01-17-2016, 11:19 AM   #234
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QuoteOriginally posted by Digitalis Quote
For a stationary subject it is largely a matter of preference whether to use the full 51 point AF field or just a single AF point in single shot AF, though if you are working with shallow DOF multiple point AF is useful as even a small amount of movement can cause a subject to go out of focus so using a wide zone AF pattern is technically a superior approach to using the central AF point. Multiple point AF can give you a much higher keeper rate, especially with faster lenses, and also when you need to track a subject that is in motion with a fast lens.
Oh good then. I'll continue in my old ways, confident that holding the camera with both hands and concentrating on framing rather than shifting focus points around easily outweighs the risk of falling victim to field curvature.
01-17-2016, 01:49 PM   #235
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QuoteOriginally posted by Cynog Ap Brychan Quote
Back in the old days (and no, I wasn't around then) the F64 club used to look down their noses in disdain at milksops who used a larger aperture, in much the same way as I look down on present-day MILCsops who use an EVF instead of a proper viewfinder!
LOL. Milksops, MILCsops.
Well done!
01-17-2016, 05:51 PM   #236
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QuoteOriginally posted by Cynog Ap Brychan Quote
Back in the old days (and no, I wasn't around then) the F64 club used to look down their noses in disdain at milksops who used a larger aperture
At f/64 on average most 8X10 lenses resolve about 22lp/mm which considering the size of the negative, is perfectly acceptable for contact prints and 16X20 enlargements. The current lenses I work with these days are capable of over 80lp/mm @ f/16 which is pretty much overkill on 8X10.
01-17-2016, 06:34 PM   #237
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QuoteOriginally posted by Cynog Ap Brychan Quote
MILCsops
ooh, I saw what you did there
01-17-2016, 07:00 PM   #238
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QuoteOriginally posted by Cynog Ap Brychan Quote
Maybe you don't us auto-focus: I maybe wrong, but I thought that Helicon could use the auto-focus on cameras to take a series of shots at predetermined intervals for focus stacking.
There is some soft to tether canikon camera like this and the last Olympus cameras have this build in but even then the AF points are pointless and you only move from an initial focus with a constant pitch. The usual way is to use a micrometric rail that move the camera and the lens (manually or motorised) of this pitch between each shot then to work with a stacking software.
01-18-2016, 10:15 PM   #239
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Forget diffraction and just take the picture.

QuoteOriginally posted by Cynog Ap Brychan Quote
lol! f16 is for large format! I like to work where my lenses are most comfortable, which is usually F5.6 or f8. I'm not brave enough to venture into the murky waters of f22 or 32 yet!
You don't need bravery. If you want more depth of field, then stop all the way down and damn the torpedoes and diffraction. I'm not saying it's not there; in fact, when I test my lenses I can certainly see softness at the smallest apertures. But you know what? It doesn't matter. The photographs are what counts, and the size that you are printing, and the distance that you expect a viewer to be standing. Photographs on the web? Not an iota of visual difference; jpg artifacts are far, far worse. If I can, I will open up one stop from all the way down for a little more sharpness, but I think, if you look at my cactus photographs, they are sharp enough. photography by andrew sharpe . I'm normally using a macro takumar 50 f4 preset (1:1), and an SMC macro takumar 100 f4. Modern macro lenses should easily be able to match what they can do.
01-18-2016, 11:50 PM   #240
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QuoteOriginally posted by Digitalis Quote
At f/64 on average most 8X10 lenses resolve about 22lp/mm which considering the size of the negative, is perfectly acceptable for contact prints and 16X20 enlargements. The current lenses I work with these days are capable of over 80lp/mm @ f/16 which is pretty much overkill on 8X10.
But your sensor is susceptible to diffraction around f/5.6. That is exactly why large format lenses and digital world are not working together that well. Pixel pitch in micron basically equals the f-stop number where diffraction becomes visible. Two f-stops later it becomes obvious.
Using film, resolution is much less than sensor pitch of 6 micron.
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