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Forum: Troubleshooting and Beginner Help
01-19-2024, 04:10 PM
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Probably one of the best videos out there
Youtu.be
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src="https://www.youtube.com/embed/EjPsP4HhHhE?controls=1" allowfullscreen>
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First we really need to know if you are shooting raw or jpg.
If you are shooting raw how the highlights clip can be very camera specific.
Here is a image taken using ETTR so that I am not clipping and capturing the best as to preserve as much data in the dark areas.
If I was to use this as a gauge as to how the image would look one would come up with the idea that there is a lot of clipping
Shot with the pentax K7
But if we look at the raw data as you can see that there is no clipping. As you can see there is a big difference in raw and processed jpg ( what is being displayed in raw converters and what is found on the back of the camera)
Next we have to look at another area that will cause you clipping, the color space
When we look at what just the color space and how it impacts what we think we see there may be no problem with clipping.
I know all this will sound complicated but the biggest take away is that 99% of all histograms out there are only showing you the distribution of your tonal range within a color space of a processed image. Clipping can be introduced along the chain by
How the camera manufacture uses the sensor
The profile used by the manufacture to create color.
The white balance used at the time of capture or at the time of processing
And the very size of the color space selected at the time of processing.
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Forum: Pentax News and Rumors
04-05-2024, 11:22 PM
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It really depends on the separator mask found in front of the AF unit, This will limit the amount of light that would reach the sensor if the mask is F5.6 then no more light coming in from the lens will not make it to the sensor even if it is a F1.8
Most masks limit to around ƒ 6 to ƒ7.5
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Forum: Pentax DSLR Discussion
02-18-2024, 02:23 AM
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It was not ETTRed the one image was under exposed by nearly 3 stops
But closing the gaps will change the tonal value of your colors also. I will repeat this there is only 3 stop difference between white and middle grey and not 5 stops. Zones 9 and 10 are tonal values that are not white but lighter than white, spectral highlights and light sources as described in Ansel's Zones. Remember these are measurements from middle grey and white spectral highlights (zone10) of course much brighter than white because they are basically a reflection of the light source pointed at the camera.
Here are the measured values of a color checker target, the white patch on the target measures as LAB 96,54 -0,425 1,186 that put it at 95% or 2.5 stops from middle grey. White with a 100% will put it at Lab 100 that is 3 stops from middle grey. there is no 5 stops. So what are you trying to compress ?
If you don't believe me that the white target is 2.5 stops from MG all you have to do is decrease your exposure by 2.5 stop mechanically with your camera and that white target is now middle grey.
If white 9.5
neutral 8
neutral 6.5
neutral 3.5
black 2
Do not hit there targeted lab values that means your yellow wont hit L81.73 , your red won't hit L42.10 and your orange won't hit 62.66 so of course they won't hit the correct tonal range as your correctly exposed image it is as simple as that.
Your white 9.5 has to be 9.5
your neutral 8 has to be 8
your neutral 6.5 has to be 6.5
your neutral 3.5 has to be 3.5
and your black 2 has to be 2 or everything will not be correct.
So are we shocked that everything else looks off when you are trying to compress everything?
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Forum: Pentax DSLR Discussion
02-13-2024, 12:38 PM
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Forum: Pentax DSLR Discussion
02-15-2024, 02:58 PM
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You do not have to create a new tonal curve for this.
here is an image that was ETTR at 0.5 sec
here at 1/3 sec
and at 1/10 sec
The light source remained the same
that is 2 1/3 of a stop difference in exposure and not once did I change the curves
Here is an overlay of the color checker patch the bottom image is the under and the overlay is the 2 1/3 over that base exposure
There should be no need for you to create a new curve all that was done was shown in the ARC settings
---------- Post added 02-15-2024 at 04:05 PM ----------
Here I have applied a different tonal curve but the same curve was applied to both shots
And again the top is exposed 2 1/3 stops more the base
---------- Post added 02-15-2024 at 04:22 PM ----------
Here is the same image processed using silkypix using the same curve for both
And again, the top was taken with an exposure that was 2 1/3rd stops brighter
This was done very quickly and only adjust for the difference in the number of stops and not the lightness of the final image.
There could a slight difference in the accuracy of those exposures over that 2 1/3 variation
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Forum: Canon, Nikon, Sony, and Other Camera Brands
02-12-2024, 03:38 PM
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Pixel density at very low light levels can play a role but it has more to do with what the sensors was designed to do.
How the sensor is used by the camera manufacture can also play a role in how it performs.
The main factors are how much light the sensor records this determines the shot noise, how the sensor is use this can determine the read noise.
How much light can vary based on how the sensor is used most sensor with smaller pixel can store more light over the total area of the sensor ( this is why some cameras can use lower iso than 100)
Sensors that are designed for lower readnoise tend to suffer at the base DR but excel at higher than normal iso.
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Forum: Pentax DSLR Discussion
02-11-2024, 04:38 PM
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One of the first problems is what is the correct white balance?
If was to use a WB card, how I place that card in the scene there would be numerous WB readings you can obtain.
If you are going for accuracy for the temp of the light source then the WB for that source would only be correct for any white or color object that is perpendicular to that light source. Any object that is not perpendicular will have a color cast introduced from surrounding objects.
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Forum: Repairs and Warranty Service
02-03-2024, 12:14 AM
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Sorry to hear this.
My best weatherproof camera is the one I can afford to lose. I always used my oldest camera with the lens that I can afford to lose in conditions that are not variable to equipment and I still take preclusions regardless of the manufacture's promotional material.
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Forum: Canon, Nikon, Sony, and Other Camera Brands
01-30-2024, 10:08 PM
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I feel just about the opposite of you. Sigma in the last 10 year has really pushed OEM to up their game. 40mm 1.4, 85 1.4, 105 1.4, 135mm 1.8, 500mm 4 150-600 they really forced OEM hand.
I have put the 150-600 sport against several lenses in the $4000-9000 and it really comes down to the technique rather than the lenses used.
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Forum: Pentax News and Rumors
01-26-2024, 09:37 PM
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Forum: Pentax DSLR Discussion
01-18-2024, 10:26 PM
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The funny thing is at this time I have no interest in ML. I have look at then and even like them but I just don't have the time or money to pick one up.
One of the last cameras I have purchased is another used D4 for under $1000 my first one is somewhere around 800,000 clicks the second one is sitting at 120,000 by the time it is dead I may be looking at a D4S or D5 and hoping it can be had for under $1000.
These cameras are still very good at what they do. I understand that ML has its advantages, but I make do with what I have.
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Forum: Pentax News and Rumors
01-17-2024, 04:42 PM
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Has more to do with processing and how the image was resized.
What size of film was used and how large the print is what determines how smooth the image will appear.
Take a 4x5 printed at most common output sizes exceed most digital in the sharpness in the edge and those transitions. How smooth the image will appear is determined by the enlargement to create the prints and the quality of the equipment and the dedication of the technician.
Take Portra 160NV using 4x5 PGI is well below the threshold most people can see when enlarged by x4.1 to 16-20inch that most good equipment will produce edges/transition with very little smoothness and better than most ditgial cameras outthere.
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Forum: Pentax News and Rumors
01-17-2024, 02:24 PM
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One of the problems is that what people think of the look of film is the grain look, while this is true for small formats when we look at larger formats there is no grain look to the photograph. If I use Portra 160NC there is no grain look all the way up too 16x20 the PGI
(print grain index) is well below what people can see when used 6x6 and above . And how this grain looked was highly dependent on my exposure management used and pushing as much light to be converted into usable information for development. Many of these when printed had what many would call a digital look as to how clean they look. Surprise a film that has a digital look.
Looking at images taken with a 20-24 camera they are pushing the PGI well below what one can perceive and produce stunning images without any grain whatsoever.
With Digital we start to get into what many people see as the digital look is over sharpening, over saturation, and tone mapping, What color profile, the contrast and the curves used can also play a role in how that image will appear in digital, similarly what film, how it was used, how it was developed and how the print was made really can change how that image appears and how filmy it looked.
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Forum: General Photography
01-17-2024, 11:03 PM
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My early Christmas present was 2 Godox AD300, one Godox AD600, 2 Sirui DK28 light stand and several modifiers.
Dang that stuff sure adds up in a hurry.
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Forum: Pentax News and Rumors
01-13-2024, 03:20 PM
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When photographing Paintball it was not hard to rack up 2000-5000 in 7 hours, at the most FPS I usually only shoot a burst of 3- 5 for average shooting.
If I only shoot 15 frames per person for a team of 10 that is 150 frames x 2 teams that is 300. 300 times 8 games that is 2400. 15 frames is not very much if you have to include key action that includes main players and placement of those players in front of key sponsors banners then it can be as much as 10-15 frames just to acheive that in a single action set times 15 to 20 times during a single game. with this included it is not hard to push 5000-8000.
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Forum: Pentax DSLR Discussion
01-11-2024, 11:47 PM
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Yes Canon sensors did have a rather higher noise level then Sony for that era this is what limited the DR of that the sensor was able to record. But this did not stop the larger sensor from recording a larger signal for the same exposure.
This noise really did not come into play until that read noise exceeded the shot noise from the light, this is what capped the noise floor on their sensors DR. With Sony starting at base iso the read noise really does not change.
Where this read noise really becomes prevalent for the Canon sensor is at the 12 stop DR range limit, most images don't require this amount of DR. Because the Canon sensor records more light for the same exposure it has a better SNR up to the point that the read noise becomes the prominet source of noise thus limiting the DR with which the sensor can record.
But what happens to the range that is not limited by the read noise of the sensor and has recorded more light, very simple it has a better SNR
Pentax K-5 vs Canon EOS 6D vs
It also help reduce noise for color reproduction.
Pentax K-5 vs Canon EOS 6D vs
And better tonal range
Pentax K-5 vs Nikon D4 vs Canon EOS 6D
Most cameras are iso invariant, it is just at which iso that happens for the 6D this is around iso 1600 with the k5 it is around iso 100 the nikon D4 this happens around iso 1600. This is when we start to see a shift in how much DR the sensor record and we see a bump it that limit. I added the D4 to also show how DR at base iso may not be the only measurement of sensor performance, as you can see that if you are shutter speed limited, this means that you are required to increase the iso to maintain that shutterspeed there can be a IQ boost to sensors that do not have any great base iso DR.
Pentax K-5 vs Nikon D4 vs Canon EOS 6D
This boost is what draw people to shoot with these kinds of sensors mainly for action that require DR
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Forum: Digital Processing, Software, and Printing
01-06-2024, 08:44 PM
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About the only filters I use on a DLSR camera is a CC30M or CC40M color filter. This acts as pre white balance that will more evenly so that the red channel is saturated to the same level as the other 2 channels. Under most shooting conditions the red channel in most modern sensor the red channels can be underexposed by 1 to 1.5 stops. The pre wb of the filter will allow more light to fall on the red pixels this in turn decreased the amount of noise in your raw conversion.
I would also look at using a Uniwb What is UniWB? | DSLRBodies | Thom Hogansetting to start off your raw conversion. This would give you a more accurate conversion for the luminosity values of the object based on the light reflecting off of it. Without the WB change red objects in warner light will have a higher luminosity value, while any blue will have a lower when using a daylight wb.
If a shadow WB is used the blue will be lighter while the red will be darker
Using a color filter on other than the one above you can be introducing more noise into your image, If B/W conversion is used you do not run the risk of introducing noise. with sensor you really want to saturate the sensor and process after .
With a monochrome you have no option other than to use color filters to alter the tonal values recorded as you cannot post process something that was not recorded
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Forum: Pentax News and Rumors
01-05-2024, 09:27 PM
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It is half the weight because the 40-150 ƒ4 captures 2 stops less light.
Now on the other hand if we try and replicate the 70-250 ƒ 4 lens you would need the 35-100 ƒ2 and weighing in at 1652 g that would put the M43 at 2249g
Heck with the K1 and the 70-250 ƒ4 you could add the 28-105 to the bag and it would be around the same weight.
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Forum: Pentax News and Rumors
12-30-2023, 08:51 PM
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Focus stacking was done with Film.
was also done with film.
You would be surprised as to how much image processing was done in the height of film photograph.
It was not to uncommon what I would use 2 to 4 exposures on a single negative or slide of film.
In the darkroom it was not to uncommon for me to use 2 to 3 different negatives to a single print.
---------- Post added 12-30-2023 at 09:57 PM ----------
What do you think a image sensors is sensitive to hmm light ?
Photo-sensitive paper is also reduced to bits those that have reacted to light and those that have not and the very same to film, the very same as the one and zeros in the imaging sensor
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Forum: Pentax K-3 III
12-27-2023, 11:33 PM
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With Group area af is selected and only in AF-s it will look for a face, group are AF acts as a cluster of AF point that reach as a single large AF point. With Nikon you also have subject detect in Auto area AF both in AF-s and AF-c
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Forum: Pentax SLR Lens Discussion
12-23-2023, 03:33 AM
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One of the way I like to calibrate is the Dot tune method
Youtu.be
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src="https://www.youtube.com/embed/7zE50jCUPhM?controls=1" allowfullscreen>
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After reviewing your image again I would say that you have 2 problems one again is focus error and the next is noise.
If you take care of the focus error you may not need to stop the lens down to see the improvement in your image you are looking for.
The next would be the noise, from what I can see you have less of a problem with stabilization as where the camera focused it appears sharp, and as for shutter speed to freeze the movement of your subject that was more than adequate.
With the 150-450 it is a larger lens that can aid in how low of a shutter speed you can go with the combination of the weight, image stabilization and what you can handhold. Using image stabilization of the camera is as much of a learning process as to how to hold, press the shutter and even how the camera is balanced in your hand. I might even suggest the addition of the battery grip as a way of further way stabilizing. I would first try adding washers to the bottom of the camera with via the tripod screw on the bottom of the camera to see if that would help you.
As a rule of thumb as to how low you can go to freeze the motion of your subject ( only if you are comfortable with IS) for larger mammals like deer and moose they are rather still and it should not be much of a problem using 1/160, if they are actively moving up the speed.
For birds my go to is can go even lower but 1/120 is my starting point, for larger birds in flight hawks, owls I may start at 1/1600 and up to 1/2500 is a good starting point. Smaller erratic birds in flight can require 1/2500- 1/4000.
It can be a real balancing act as to how you shoot but once your get accustom you many find that you might not need to stop down as much as you need and that you do not require the shutter speeds thus increasing the light you capture and reduce the noise reduction needed.
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Forum: Pentax SLR Lens Discussion
12-22-2023, 12:52 AM
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To me it looks like an AF problem if you have focused on the front deer.
I have found with several zoom lenses there is a need for calibration, this includes calibration for the distance that you are going to use the lens and at what FL you are going to shoot at.
Things get compounded as you crop and also if you are using a TC as this increases the magnification that you will be viewing the image at, so any little focus errors will be more visible.
I tend to set my AF calibration for the most common distance I will be using the lens at and also the mid point within the zoom range . I also do the same for when a TC is added.
For much of my critical work I like to use a cheat sheet that is attached to the lens hood with the correct correction for near, mid and far distances also for the FL of the lens and even how much the lens is stopped down.
On the very same sheet I also include the same information when a TC is used.
What I have found is that with lenses that can also be calibrated via a dock a game changer as you can apply corrects for different distances at different working distances. I wish camera manufactures included this function in camera for calibrations.
Often times people ( myself included) felt that many times it was the shutter speed and or technique causing some of my issues but further examination that many times it was focus error.
I have found that with stabilization that it is not too hard to get very sharp images using shutterspeeds in the 1/500 to 1/100 range
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