weasel_bar

Sunset over the Milwaukee river. Ilford HP5. 

Ducks on lake Michigan at sunrise. 

Canon ae-1, velvia 100 slide. The colors on the slide actually look like this. 

57 minutes ago, Ken Katz said:

If you look at the bottom of this page, there is an explanation as to why diffraction is independent of focal length.

https://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

I also do not have the technical expertise to explain this, but I have never seen anything to contradict this assumption.  I believe you will need to live with some diffraction impact when shooting macro in order to keep a decent portion of the subject in focus, like with living subjects such as flowers and bugs.

Thanks for pointing this out, Ken! 

Not sure what's the best forum for this topic, but here goes. 

According to Cambridge in color, a site i have found reliable, the effect of diffraction on sharpness is related to fstop, and the calculator uses fstop and magnification to calculate the aperture at which diffraction becomes significant. 

https://www.cambridgeincolour.com/tutorials/macro-lenses.htm

Notice that it does not use focal length. 

Remember that fstop is the ratio of focal length and aperture. So, for the same fstop, a longer lens will have a larger aperture. 

Recall that the angle of deviation of light past the diaphragm for the slit diaphragm diffraction is sin(theta) =lambda/d where d is the aperture width. I don't understand the physics of how diffraction causes "softness" in an image, but my first intuition would be that effect of diffraction would depend on aperture size, not fstop ratio. 

Is it true that diffraction-induced softness is a function of fstop, independent of focal length? If so, why? 

On 5/23/2023 at 4:51 AM, Jochen_S said:

Sorry, over 1$/frame (+ processing + ...) isn't what I 'd call "affordable", especially with digital competition at hand. Sure, it is somehow doable, but why?

Why? 

1) i like the look of film

2) i have film gear

3) over the last 25 years of shooting, i find myself taking LESS photos but better photos. I attribute this to slowing down and putting more thought into each shot. If I just want snapshots, i can take them on my phone or with a digital point/shoot. I use my slr to (try to) take good photographs. I might shoot 10 rolls a year, tops. The annual expenditure is not that much. I see a lot of people use their digital SLRs as basically p&s cameras, generating tons of snapshots. William Henry Jackson and Ansel Adams carried glass plate negatives weighing more than half a pound each, so they could only carry a few. Yet, they took better photos than any of us ever will. 

On 11/9/2023 at 8:16 AM, polka said:

The question is : through how many lenses goes your picture : shooting analog is the first lens, then either you scan the film, the scanner is a second lens ; or you enlarge to paper in a wet laboratory, the enlarger lens is also a second lens, or else you scan it with a digital camera, thus also through a second lens, or you use a slide projector and you have also a second lens. In any case each second lens adds some convolution to your original picture on film and thus reduces somehow its resolution. 🙄So, doesn't the only way seem to shoot directly digital ?😉

Comparison is not valid for projected slides. The second lens would be required to project an image captured by a digital camera. 

For printing agree about the second lens, at least in theory. 20 years ago, I used to get optical color prints made by a local lab. I remember the achieved resolution being very good. One could extract a lot of fine detail from a negative. Scanning gives more control over color, contrast, etc. 

I would guess that the effect of second lens depends greatly on the quality. My "new" nikon coolscan gives much better results than my previous scanner, due to much better lens, despite the ccd sensor having a lower nominal resolution. For slides, I noticed a difference in analog projected image quality between different projector lenses. My Golden Navitar gives better results than the kodak lens i have

Lake George in the Adirondacks. 

Cabin ae-1, kodak elite chrone slide. I think the lens is nFD 28/2.8

I bought a nikon coolscan v on ebay. Actual achieved resolution is somewhat better than plustek (somewhere between 3600-3800 dpi vs 3200). But the real difference is in other aspects of image quality-much less noise, higher de facto resolution despite smaller files due to less bloat, and better dynamic range. Pretty happy. 

5 hours ago, Bettendorf said:

I'll add a third to Niels' comment.

Just the other day I received an email about this new starter kit, and I'm beginning to think about making the switch.

https://www.freestylephoto.com/8501236-Negative-Supply-Essential-35mm-Film-Scanning-Freestyle-Exclusive

 

This setup looks nice. I don't have a digital slr, and I'm stalling as long as I can. Shooting my old canon fd gear. In fact, bought a used Canon ftb and had it CLAd. Being mostly metal, it doubles as a self-defense weapon. 

4 hours ago, James G. Dainis said:

 I used to make Cibachrome prints for friends from their slides until I got tired of hearing, "But these don't glow like the projected slides do." Project a slide of a light bulb on a slide screen and the darkened room lights up from the light reflected off of the screen.  Stick a photograph of the light bulb on the wall and what do you see? Nothing. The room remains dark. You've lost the glow.

I unfortunately never had the chance to make Cibachromes of any of my landscapes. I don't know if anyone still offering this service.

For over 10 years, I've been scanning my film with Plustek's Opticfilm 7200i. It's CCD sensor has a resolution of 7200 pixels per inch. I started reading some scanner tests, and learned about the large difference between nominal resolution and actually achieved resolution https://www.filmscanner.info/en/FilmscannerRangliste.html

So I bought a 35mm slide made by Silverfast of the 1951 USAF target intended to test the resolving power of optical systems 

https://www.silverfast.com/products-overview-products-company-lasersoft-imaging/silverfast-resolution-target-usaf-1951/

I found the following for my 7200

set scan res / actual res

7200 / 3250 (45% of stated resolution)

3600 / 2300 (64% of stated resolution)

3250 is plenty for me, if actually achieved with no bloat. I could print my 35mm shots at 11x17. Other than some rare frames of velvia 50 shot with a tripod, I doubt I have many images that would be of high enough technical quality (not artistic quality) and detail to justify any bigger.

Here's the rub. in order to get 3250 ppi of resolution, I have to scan at 7200, and the image generated has a ton of garbage pixels. I found that when downsizing, there is resolution loss. For example, If I downsize 7200 to 3600, the resulting image has a resolution of about 2900 ppi according to the USAF chart, so I've lost 11% from the originally achieved 3250. This seems to be true even using Resize Magic, which uses a Lanczos-like algorithm, which gave somewhat better results than bicubic. Downsizing a 3600 ppi scan to 1800 resulted in essentially no resolution loss. So, even if a 7200 ppi scan has enough detail to print fine details at 300 dpi at 11x17 size, the downsizing results in what I think will be effectively printing at 250 dpi resolution. Which maybe isn't the end of the world.

So I bought a Pacific Image Primefilm XEs. The XE is supposed to be the same as the Reflecta 10T, which according to tests from the above website yielded resolutions of 4100 at the 5000 ppi setting. The XEs is apparently the newer version of XE. I was grossly disappointed to find that at 10000 and 7500 ppi, the resulting resolution was 3650--only barely better than my bluecollar Plustek. At 5000 ppi, the quuality was even worse. Just like the Plustek, the scanner generated far more pixels than it did actual usable information.

I looked at some used Nikon coolscan Vs, but they are now fetching exorbitant prices. 

I guess I'll just project my Velvia slides so they can be viewed as intended, and force my wife to watch slide shows. I bought some used ektagraphics for around $50 each, including shipping. There's still nothing, NOTHING, like a projected image. 

When film equipment dies or I die, whichever comes first, I'll quit and find a new hobby.

Chimney Tops at Smoky Mountain National Park, Fall 2022. Fuji Velvia 100, canon ae-1

ilford HP5, canon ae-1

On 4/6/2023 at 11:16 AM, eddy_d said:

And you think Digiital is cleaner for the environment? Cell phones , digital cameras and Computers have lead and cadmium and other hazardous materials in them. They are not bio degradable and are filling up landfills. The technology is developed at break neck speeds so what is coming out now is already obsolete and then discarded for the new. Computers, and other E waste are listed as hazardous waste where I live and cannot be thrown out with the regular trash.

The world is screwed. I say this as an environmentalist who donates lots of money to conservation and has a kid who I hope won't live in a garbage world. 

Most people went digital for convenience, not because they care about ecology or anyone except themselves. Film is bad for the environment. Probably so is digital-and all electronics.-agree regarding the probably very bad impact of the rush for rare earth metals. 

The only thing not bad for the environment is to kill oneself and one's kids right now, and compost the remains 🙄

On 4/22/2023 at 10:32 AM, AlanKlein said:

What does the differing calculations mean to the average photographer?  For example, box speed ISO 100 on reversal vs positive color film means what?

It may not make any practical difference. However, it provides insight. After reviewing the excellent resource provided by @Dustin McAmera I surmise the following.

For color slide film, the reference point for calculating ISO is the minimum density, which determines WHITE point. Thus, if the characteristic curve is reasonably linear in the middle, I think the light meter will hopefully place mid gray at 18% transmittance of the minimum density. My guess is that this means the midtones will look right to the eye compared to the highlights. How much blacker the image will go in the shadows will vary by film stock, since the Dmax is different. It also illustrates explicitly how, for the same box speed, contrast and tolerance to exposure variation are influenced. 

For example, I ballpark the following from characteristic curves

Velvia 100: Dmin=0.2. D=0.4-->logH= -0.6. D=2.2-->logH= -1.5. LogHm= -1.05-->iso ~100

Provia 100: Dmin=0.2. D=0.4-->logH = -0.4. D=2.2-->logH= -1.7. LogHm=--1.05-->Iso ~100

For the same box iso, velvia goes to a density of 2.2 (1/150th transmittance) at almost a full stop before provia does. Even though velvia has a higher Dmax than provia, at a density of 2.2, your eyes will probably not discern much detail, and you're going to perceive black. So velvia goes "darkish" quickly. This might explain why people tend to err on the side of overexposure with velvia, compared to other slide films.

For color negative film, the reference point for iso is also the min density. But here, the min density determines where the SHADOWS lie. Also, we use a single point rather than a midpoint. This may be helpful, since the response stays very linear for many stops of overexposure. Different color neg films have different densities for "mid-gray" exposure, depending on the slope of the curve after Hm.

11 hours ago, Dustin McAmera said:

https://archive.org/details/Manual_of_Photography/page/n319/mode/2up?q=ISO

This is extremely helpful. Thank you! 

Does anyone know how ISO is defined for slide film? For negative film, ISO is defined by the speed point, where density is 0.1 above baseline. According to Wikipedia, for slide film, ISO is "determined from the middle rather than the threshold of the curve." I tried looking up the definition on ISO website, but it costs 61 swiss francs to find out. Does anyone know what is the technical definition of ISO for reversal film?

@Gus Lazzari thanks. I talked to the technician, who said it's "shutter bounce." I think you are referring to the same problem. Sent back for repair. Fingers crossed.

Ok sorry for the double post. And thanks to all for the information. 

Some of them could have been 1/500 or 1/1000. The bands have different widths on different frames, but always go to edge. So probably varying by shutter speed. What's the solution? 

looking at the FTB documentation, and it has a horizontally traveling shutter., which might lead to a vertical band if it's in the way during exposure. So could it be the shutter timing is off?

correction to above. THe band is visible on some frames in the subsequent roll as well, with the same camera.

shot some fuji reala with newly refurbished canon ftb. weird band of underexposure on several negatives, on the right. Have not seen this before. is it related to the quick loading device? It is visible on many frames on two separate rolls. see attached.

I shot a roll of Fuji Reala, and several frames have an odd band of underexposure at the left edge. i was using a newly refurbished canon ftb. I have never had it happen before, nor on a subsequent roll of reala, which I shot with (i think) the same body. See attached. 

Anyone know why this happened?

sunrise on lake Michigan in Milwaukee