Ugly Hedgehog - Photography Forum
Home Active Topics Newest Pictures Search Login Register
Posts for: JimH123
Page: 1 2 3 4 5 6 ... 431 next>>
Mar 24, 2024 19:49:31   #
Niklon wrote:
I REALLY like the second one much better.


Thank you for your comment. I am leaning towards the 2nd one also.

I have tried other ways of affecting the contrast and making the blacks become blacker, and the Gamma Correction slider seems to work better than the more conventional approaches. But I have never read anywhere anyone else using this for B&W. Perhaps others do this too. But I haven't read about it anywhere.
Go to
Mar 23, 2024 23:37:23   #
joecichjr wrote:
I couldn't tell you.
I am mad at myself that I did the 720nm, because it is almost totally limiting.
Can screw on any other nanometer filters unless they're above 720.


Since the 720nm is blocking all the wavelengths shorter than 720nm, you won't see any different effect. For instance, if you were to try 590nm screwed onto the lens, then the lens would pass 590nm and longer to the IR filter in front of the sensor. And that filter would eliminate 590nm to 720nm leaving only wavelengths longer than 720nm.

But keep in mind that many or most IR filters do not have a sharp cutoff. It costs more money to make a filter with a sharp cutoff, and a sharp cutoff is not necessary to enjoy the IR effects.
Go to
Mar 23, 2024 13:21:28   #
Here is another example. Image shot in RAW with a monochrome sensor modified camera. RAW file was converted to monochrome DNG file with an application called Monochrome2DNG resulting in a somewhat flat B&W image.

The second image is made using only the Gamma Correction in Photoshop plus the exposure adjust since changing Gamma makes the image look darker. Only question would be whether too much Gamma adjust was used and whether it should have been slightly less?

Since I have just discovered the Gamma Correction effect on mono files, I haven't yet decided what is just right and what is too much.

Thinking that perhaps I adjusted Gamma too far, image #3 is reduced a bit. Perhaps it is a better rendition?

Original with no adjustments

(Download)

Using only Gamma Correction

(Download)

A little less Gamma Correction

(Download)
Go to
Mar 22, 2024 21:16:40   #
I really don't have much experience using the gamma correction in Photoshop, and don't really understand exactly what one would normally use it for. But I decided to see what it would do to a B&W image. The first one is a bit flat. And on the second, I see that the blacks got blacker in a way that I think improves the result. B&W benefits from higher contrast and the gamma correction certainly had an effect on contrast, but in a way that I couldn't duplicate using the contrast adjustment, or fixing the blacks and shadows, or adding dehaze and clarity.

In Photoshop, you will find the Gamma Correction in Image/Adjustments/Exposure. I slid it slightly to the right while watching what it was doing to the blacks and stopped before it looked like it had been slid too far. Then tweaked the exposure slider found in the same popup box and brought it back to an exposure that looked correct. But the result was that the blacks were suddenly better.

The camera used was a Sony A6300 modified by removal of the CFA making it a mono sensor. And was used with a Samyang 18mm lens. The UV-IR filter is also removed so it is IR full spectrum, and a 590nm filter was used. DxO Photolab 7 was used on the RAW image and then was loaded into Photoshop for the gamma adjust.

It was about 50% cloudy today when I took this, and the IR effect was thus weaker than would have been on a sunnier day. The Sycamore trees in the image don't yet have leaves, but you can see the little fuzzy balls hanging down left over from last season.

Original B&W result is a bit flat

(Download)

Result obtained after dragging the gamma adjust in Lightroom a bit to the right

(Download)
Go to
Mar 11, 2024 01:22:38   #
fcatmandu wrote:
I had a conversion done some years back but don't remember which nm i had done. Is there a way to tell in the camera or do I need to go back to the company that did the conversion?


There certainly is. Check out this youtube video by Rob Shea. He provides a file to download in which you can take a picture of your monitor and to figure out where your camera fits in. One thing he didn't say. I think you should pick a sunny white balance to do this test. If you do a custom white balance, the results may shift that he is showing.

https://blog.robsheaphotography.com/2023/08/05/which-infrared-filter.html

There is also another way that I can make a determination that can be used by someone that uses multiple filters. I have a full spectrum and can use any filter I want to use. But I find that if I just take a picture with a known white balance such as Sunny, and just look at the image before I do any channel swapping, the different filters produce a overall color cast that is different for the different filters, but is constant for a given filter. That way, if I have forgotten what filter I used, I just look at the unprocessed image and can immediately tell what filter I used. You would need to shoot several images with different filters to produce some sample images to have something to compare to.

Note: I shoot RAW and do not do custom white balances in JPEG which could drastically affect these color casts. And also, with RAW, I find no advantage to custom white balance on green grass for instance. RAW allows me to shift colors as far as I want. I did some experiments where I compared end results using sunny WB, then custom WB using green grass, and then used cloudy, tungsten and florescent WB's. Then processed the results, in each case, I got the same end result, and the work involved was no more difficult.

But if you shoot JPEG, this won't work.
Go to
Feb 27, 2024 13:58:55   #
The winter rains have been gone for several days now, and the roses are leafing out, and even provided a clump of the first roses of the spring. I like how the new growth starts out red and soon turns to a beautiful, shiny green. The weather is feeling like spring and its pleasant to be outdoors again. And on the first image, I see the flies are already here.

Of course, by mid to late summer, these leaves will no longer be so shiny green as the sun bears down on them day after day, and insects chew holes in them. But for now, I love it.

Using the Nikon P1000 for this. It is actually quite good for closeups in that I can pick a huge range of focal lengths to work with which translates into how much working distance I want to work with.

These are taken about 20 miles south of San Jose, CA.


(Download)


(Download)


(Download)


(Download)
Go to
Feb 27, 2024 02:02:27   #
chrisg-optical wrote:
That would be one hell of a strobe or LED light to reach the moon.


And make it all the back again!!! That's roughly a 500,000 mile round trip. And then the firing of the flash aprox. 3 seconds before the shutter activates.
Go to
Feb 26, 2024 22:19:49   #
User ID wrote:
Nice lighting. Strobe ? LED ? Unique !!!


Ya, Sure! Many, many moons ago, while in the Navy, we had a full eclipse of the moon while crossing the Pacific. It was beautiful. And the best place to see it was up on the boat deck where it was really dark and where many brought out their cameras with flashes. Flashes firing like crazy. I wonder just how many of them got a keeper???
Go to
Feb 26, 2024 14:31:35   #
Here is where you can find that strap wrench which User ID showed earlier in the thread:

https://www.walmart.com/ip/Hyper-Tough-4-Adjustable-Strap-Filter-Wrench-Model-4208/124886813
Go to
Feb 14, 2024 00:52:14   #
dwmoar wrote:
You indeed can on a Canon. It is even easier if you use something like this. This setup will set you back about $60.00

You can also set the aperture before reversing the lens by using the DOF button and then removing the lens. The aperture will then remain at what ever size was set when you pressed the DOF button and removed the lens. So yes it can be done with a fully electronic lens. It is just a pain to do it. The setup in the image is much easier to work with and all the EXif data remain intact.
You indeed can on a Canon. It is even easier if y... (show quote)


Novoflex offers adapters like this, but they cost a lot more than $60. They offer Canon, Nikon and Sony. I didn't look for any other cameras.

Just Google "Novoflex reverse adapter canon" or nikon or sony to see them. Maybe someone else makes these. I didn't search for any of them.

When reversing a lens, there is a limited range of focal lengths that this will work. Highest magnification comes from shorter focal lengths. The following FL's work: 28mm, 35mm and 50mm. As you move to longer FL's, they will not obtain focus as the focal plane moves into the lens.

Manual macro lenses can be cheap enough that you can bypass reversing lens altogether. In the case of macro lenses, the longer the FL, the longer the working distance. I have several manual macro lenses in different focal lengths, and they really do work well.
Go to
Feb 13, 2024 15:45:44   #
Longshadow wrote:
Interesting.
I don't think I'd remove the lens with camera power on.


It also does not work for all lens manufacturers.
Go to
Feb 13, 2024 15:44:44   #
Bohica wrote:
Years ago (50?) I used to use a ring to reverse my lens on the camera for macro. Going through some boxes in the closet I came across a couple. How different would it be using these rings on a DSLR


What camera are you using? There are adapters that connect to the camera via the lens mount, and have an extended cable that attaches to the lens mount on the lens, allowing the camera to control the aperture when the lens is mounted backwards.

OR

You buy an inexpensive manual lens which gives you manual control of the lens aperture. There are wonderful manual lenses available that work great for mounting backwards.

And then on the camera, use live view for focusing.
Go to
Feb 8, 2024 19:18:23   #
joecichjr wrote:
Exactly! I wish I had know then what I know now when I was getting the camera converted. I would have done a full spectrum and not be so limited now....


What filter did you have installed? For instance, if you chose 590nm, you can add any filter with a longer wave length, and will act as a camera that new longer wave length. Example, if you have a 590nm conversion, you can add a 636nm, or a 720nm, or even an 850nm.

But it doesn't work the other way. If you have a 720nm, you can't add a 590nm.
Go to
Feb 7, 2024 16:08:09   #
JohnSwanda wrote:
AI images don't belong in General Photography. People could post all the AI generated images they wanted there, and claim it's to show their impact on photography.


I prefer to have these in general photography as it shows us what is trying to be passed off as real photography. Put it somewhere else and I would never know about it.

And the agree that this result is really poor.
Go to
Feb 4, 2024 17:02:51   #
kymarto wrote:
Each pixel has a single luminance value and a single chrominance value. Other things being equal, the only advantage to larger photosites is better low light response. Things like color bit depth and dynamic range depend more on sensor design.


Actually, each photosite only has a luminance value. It is only luminance values that are read during the sensor readout. During Demosaicing, the process knows what color filter is over each photosite and then mathematically determines a Red, a Green and a Blue value for each pixel in the output file by averaging some number of photosites together, where it only averages red sites, then only green sites and then only blue sites..

Please note that the Demosaicing process follows rules and is determined by the camera manufacturer and may vary from one model to another model. And it may vary between different Software suppliers. In fact, RawTherapee provides about 10 different Demosaicing algorithms to choose between.

Also, when a new camera is released, the camera manufacturer is responsible for releasing Demosaicing rules for the Software manufacturers to follow. This is why you see a new camera work in JPEG only at first, and then later, RAW files can be used after the manufacture releases the rules and the Software people incorporate it into their product.

This means that demosaicing is also not an exact science. Colors may vary from one process to another process.

Also, fine detail can be impacted too when Demosaicing uses a greater number of pixels to average to get better color. This is a trade off that has to be considered by the manufacturer. Also considered is how it senses edges since the averaging may have to be adjusted. The process is not simple.
Go to
Page: 1 2 3 4 5 6 ... 431 next>>
UglyHedgehog.com - Forum
Copyright 2011-2024 Ugly Hedgehog, Inc.