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Forum: Non-Pentax Cameras: Canon, Nikon, etc. 06-07-2019, 09:56 PM  
Nikon [5] vs Pentax [1]
Posted By Ian Stuart Forsyth
Replies: 91
Views: 3,056
Amazing how an individual will start to up playing a feature and that it will somehow persuade a user of another brand into pentax with this feature. When they look at the cost to include a camera body with such a feature its just much cheaper for them to stay with what they have and add a $300 tracker. Or even keep using my K5 and pickup a tracker is a much more cheaper than upgrading and in the end I have something that can be used with a much greater range of versatility.
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 06-06-2019, 10:51 PM  
Nikon [5] vs Pentax [1]
Posted By Ian Stuart Forsyth
Replies: 91
Views: 3,056
There is a real narrow band that the astro photographers would use the astro tracer. For wide angle work you have the problem at the outer most areas of the image will show star trails as the sensor moves and tracks the earths rotation behind the lens, many preferer that the lens and camera body move to eliminate this. There is also how they capture their final image which can entail several exposures that one would have to reposition the framing of camera when using astro tracking. With a tracking mount there is no need to reposition the framing in-between frames this will help to limit problems also with stacking wide angle captures.

With deep sky shooting having the entire rig also track can really elevate a lot of the hassle of recomposing the shot in-between exposures that often entail several hours of exposure time with 20-100 stills. For deep sky tracking photographers usually have their locations planned out in advance and have easy access to as they often use that location for several nights and don't need a compact and portable systems to do so. Many will have installed conc, pillars that they come back to setup on and are happy to let other use when the are not. For these guys $1600 can buy you a very good tracking system and with a little more $$ you can set them up for guided work ( laptop and guiding camera).

If you are interested in a more cheaper and light weight $400-600 can get you setup and many can be setup for guided work. One of the additional benefits of these is what is known as half time tracking this is where you can track at half the speed to place the rotation blur half in the background and half in the stars which is a nice workaround if you are placing any landscape within a single frame. One of the reasons why I picked of a tracking mount was for time-lapse video that evolves panning, it just so happened that it can also track and be converted to a guided mount.

If you are willing to work outside of these constrains then IBS tracking can work for you.
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 06-06-2019, 09:10 PM  
A close look at the LG8600 sensor
Posted By Ian Stuart Forsyth
Replies: 6
Views: 360
It was from a LG 8600 cell phone
LG 8600 Chocolate Flip Reviews, Specs & Price Compare
I have no clue as to designed and built the sensor
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 06-05-2019, 11:50 AM  
A close look at the LG8600 sensor
Posted By Ian Stuart Forsyth
Replies: 6
Views: 360
Found some markings F1 840 1 here I used photo stacking to increase a little more resolution




Interesting features along the top and right side of the chip


More features



While I had the setup going I redone the pentax K7 sensor also

---------- Post added 06-05-2019 at 12:24 PM ----------

Here is the K7 sensor which is a Samsung sensor

Reference image


Now the closeup






here is a crop of the photosites




in the next few months I should have images of the K5 sensor to add
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 06-05-2019, 10:37 AM  
A close look at the LG8600 sensor
Posted By Ian Stuart Forsyth
Replies: 6
Views: 360
It's Ant-man
Just a little humour :)
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 06-05-2019, 02:12 AM  
A close look at the LG8600 sensor
Posted By Ian Stuart Forsyth
Replies: 6
Views: 360
Just to give you some perspective on its size




















Forum: Photographic Technique 05-23-2019, 02:30 AM  
Undies,Histograms,Reds,and Clipping.
Posted By Ian Stuart Forsyth
Replies: 26
Views: 2,623
I will add that there has been a shift in the temperature of the light in between the 1st and the 7th image as you can see in the raw histogram, it is slight but it is there .
This has changed how the areas that are in more direct light from above show a slightly different color cast, while the areas in that are mainly being supplied light from the reflected surfaces from around the sweeter don't have this color shift. this would tell me that there is a stronger light source for the last image from directly from above is warmer.



Here I have WB for that difference and just applied a tonal adjustment to reveal the detail in the red sweater ( just quick tweaks) , one side the first image and the other the 7th image mirrored. Other than motion blur and different focus the 7th is fully recoverable with a little more wiggle room allowed in the exposure before the raw is clipped.

---------- Post added 05-23-2019 at 03:02 AM ----------



Where you think you are showing chipped and what you think is clipped is not from being overexposed and blowing the red with a that exposure , where a lot of people think reds are overexposed are not found in the areas contained with in the raw files reds.

For this image I used a cc30m filter to pre WB the light so that the red channel is closer to the green channel as to where they would clip this way I can maximise the red channel information I can store in my sensor.


here is what it would look like without this prewb filter

my greens are way out in front to clip in normal daylight first.

When I have done everything to put the priority on clipping the reds it does not show up in the red that you have posted above, if you look at my first image I have clipping shown as blue patches in my first image.
That bump in my red channel in the first image is all of that data where there is the very lightest pinks around that blue.

For me this would be the perfect exposure for the raw file when shooting this flower.
Forum: Photographic Technique 05-23-2019, 12:02 AM  
Undies,Histograms,Reds,and Clipping.
Posted By Ian Stuart Forsyth
Replies: 26
Views: 2,623
I had a look at the image with the largest exposure in the group 1890 and it is still around one stop from clipping the red channel
Forum: Pentax DSLR Discussion 05-22-2019, 11:38 PM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
It really depends on your WB for this image it looks like you are using daylight WB so your red channel is being multiplied by a factor of 2 stops an I suspect this is why your reds are so far to the right

---------- Post added 05-22-2019 at 11:43 PM ----------



Again its more than likely the raw converter that is what you think is clipping the reds because of how WB works, as for the exposure clipping the raw data its more than likely that its at least underexposed by the WB and for daylight WB that would be around 1 to 2 stops
Forum: Pentax DSLR Discussion 05-21-2019, 12:11 AM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
And if you take a look your whites they will be overexposed well before your reds and that is my point if your whites are not clipped then your red are not unless your are under some kind of artificial light.


here in daylight light I have clipped my whites on purpose and even in to the first grey while nothing in the red and yellow flowers have clipped
Forum: Pentax DSLR Discussion 05-19-2019, 11:53 PM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
Basically yes, but the problem lies with finding out what is overexposed.
And the main point is that it take a lot to clip reds in outdoor light, if your whites that are being lite the same as your red subjects and the whites are not clipped then your reds are not also.

---------- Post added 05-20-2019 at 12:04 AM ----------



Yes but just like Tony has stated, without setting up the raw converter to show you a more accurate representation of what unprocessed raw data looks like its hard to know what to base what you can recover and what you have.

One of the problem with the red is that they are in themselves underexposed most of the time and using the method of underexposing them to recover what you may think is lost only adds to the problem your already have and is why you see less detail and worse recorded color in the red's.
Forum: Pentax DSLR Discussion 05-17-2019, 02:12 AM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
If you are wanting to use your cameras histogram I would first look at understanding what the cameras WB is doing and what happens to the color channels
How red is your red ? - Page 3 - PentaxForums.com

If you are using photoshop I would find out how much of a BLE your camera is using this way you can override the highlight headroom that is built into and that PS is using to setup the raw processing covered in the link about. covered in the above link with a link showing how to setup PS
Also consider adjusting your WB in camera until you reach a WB setting of 1,1,1 in line c628 of your exif data of your photograph and store that in your camera so you can pull it up when you need it. Covered here
How red is your red ? - Page 3 - PentaxForums.com

This would give you a pretty good idea of what your raw data looks like, then you can go about setting up the camera and what to expect when looking at the cameras histogram, If you don't want to go thru this work you might look at buying fastraw viewer















Youtu.be



This will give you the best way of knowing what your camera is doing and just as important you can find how the relationship with how the color channels clip and how they clip in different light sources, You will find in natural outdoor light the green channels is first to clip while red is less likely and the program is cheap I think for what it allows you to find out.

Once you know your raw files you can go about finding a way of setting up an exposure management system that will work for you. I use 2 basic methods one based on the histogram of my camera and the second on the cameras metering system. With the Histogram method I set it up as close as I can to what the raw data contains, again using a UniWB this way you will get a better representation how the 3 color channels fall that exposure ( use the WB for all your conditions of lighting as it does not matter). I would then go about setting up the cameras color profile to the most neutral setting. Then its just trial and error until you find out how your cameras histogram shows you raw data.

The one I mostly use is the cameras metering system, for this I find a white target while in Manual mode I meter on that white target and increase that exposure until it reads +3 in your OVF. Take a photo and look at it in your raw viewer and see how far that white target is from clipping and then keep increasing the cameras exposure until you see your first channel start to clip in the raw viewer. Now you know how many stop till clipping, for me I had to raise my camera 1 2/3 stops to clip and I like to have a safety net so I don't go the full 1 2/3 stops I use 1 to 1 1/3 and set my cameras EC to that. So now when I place my spot metering point on what I want to be white in my raw file it should read +2 2/3 to 3 with my cameras metering system.
Forum: Pentax DSLR Discussion 05-16-2019, 01:48 AM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
Sorry its not about over exposure its about displayed colors and that numeric values it occupies within a color space.

There is a difference between having a properly exposed image, the correct lightness in our final image and how we show those in a color space. Most of the time when we are photographing its the processing that has caused us the issues with reds this includes the camera profiles as I have shown when you look at the raw histograms in earlier pages.

When we are using the cameras Histogram during exposure in raw we are using it to measure saturation capacity so that we don't clip data. When using in camera histogram for in camera jpg we are trying to find the best exposure to fit the cameras color profile and color space you have selected for a given scene . With the histogram in the photo editor we are using it to placing our exposure within a color & tonal range of a color space.

There is a difference in how we use those histograms for in camera and photo editing software, If we do not use RGB values of 255 in our processed image we can be removing any details and tonal range that is found in our scene because to reproduce them those color values need us to use R 255 in our displayed image.

There is really no raw R255 value (what we can see is saturation levels of the RGB with special software) what we see in the raw converter in RGB values that is derived from using a color profile, the WB you select and how we place all that information using tonal, saturation,contrast sliders, along with the color space and bit depth will decides what data falls in at R 255.

We have to display images within a color space there can be many colors that fall into the range that R255 is required in a color space . Take this image below.
http://isfphotography.com/255.tif
everyone of those colors that we see here (much of the color ranges we have with red 255 is to large to show all of them in a image like this) we need to have red at 255 and several of those we also need either B or G to also have 255. If I where to use the histogram in my photo editorr (not cameras histogram used for judging exposure) and show R at 255 many would be telling you have clipped your reds.



In this image we need R 255 and also G255 B255, many of those variations shown above so we can see these different colors, to alter them so you wont show reds in the 255 histogram you will be clipping the size of color gamut for that color space to a smaller one, this would removing a great amount of the colors you see above , now some of them will not be altered like the ones at the very corners of the magenta, red, orange and yellows.

To put it simply if I take a photograph of the tiff file shown above which has get deal of color variations, I would use an exposure as not to clip the data we need to create the final image, Now if I want to process the file to accurately depicted how the original image looked we would need to have all of the red pixels at 255 or we will not correctly recreate the final image as it is seen in the tiff file. The reason why is that a great deal of the colors of that scene fall in the colors gamut's values that use R255 marker and a get deal of them needing ether B255 and or G255 also

Here I have deceased the red down to 254 to conform to the believe that there is clipping in the red
http://isfphotography.com/254.tif
In this smaller image the banding is less prominent because of the range of the limited colors because of the size of the image but here you can see banding in much of the colors and that is because you have clipping off the color gamut of those lost R255 values
Here I lowered it to 253
http://isfphotography.com/253.tif

All of that banding is because of the clipping of the color gamut. You will also see that in the reds, oranges and magentas that fall at the outermost regions of the image did not change in how we perceive those colors when lowered to 253. The major reason why this is, the color data that fails within those limits 255-253 values found at the outer boundary of the image are much more accurate at measuring variations than we can see.

There differences as to why we use the histogram (more importantly raw histogram) to evaluate the correct exposure for the camera and there are difference as to why we use a histogram in processing our raw data and finally the histogram in how we choose to display the final image.

Oddly enough the red colors that are the at most greatest risk of clipping when setting your cameras exposure are the ones found in the center 3rd of the first time tiff file and not the reds that everyone thinks that are clipping. Its the color gamut, your WB and other processing that does the clipping for you.
Forum: Pentax DSLR Discussion 05-11-2019, 12:12 AM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
Will also add that you have to be careful when trying to understand the histogram in a photo editor , what it means when the red is to the right and that many times it does not mean that your color red in no way means its clipping.
Here is a image

Now if we rely on the histogram of your image editing software it will tell you that you have a great deal of red clipping and that you should go about stopping this


all 3 of these colors could lead you to thinking that there is clipping in the red channel, my question to you are they really clipped. It just shows that red is at full saturation and or close to the limit of the color gamut
If you want to show these colors in your photograph than they are not and if I change them so that the histogram show no clipping then I will fundamentally change the those colors and if I am trying to accurately capture and show those colors in my image I may be decreasing the range of colors within my image if I use the histogram

Top right color #ff002f Color Hex
Top left color #ff00c2 Color Hex
Bottom color #ffc82f Color Hex

So then what the question again is what is it really mean with the red show a heavy count to the right in photo editing software ?

Here is a second image

Now if I look at the red in the histogram you will be given the idea that it all should be corrected because of how close the red is to the right

But if I want to show any range of red contained in this image I will need to have the red to the far right in the image. If not then I will lose that complete range of these reds shown in the above image
Forum: Pentax DSLR Discussion 05-10-2019, 01:30 AM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
Its has more to do with the WB if you set your WB to a UniWB then you will see the relationship as to how the 3 channels are captured, Now this will not show how much highlight headroom you have but it will give you a very accurate



This is how it would look in a raw converter

Now if you want to see how the image will appear with UniWB you can manually set up you dng file WB to a UniWB by going into the exif data and changing line C628 so that it is 1,1,1 this will tell the raw converter to select a WB without multiplying any of the color channels. Those numbers represent (RGB) so in this diagram you see that Red has a 0.40 multiply so that is over a stop of lightness being applied to that channel while the green with 1 has none.





Above is what that change to line C628 did, but you have to remember to select as shot in your WB.

This is also an easy way to find you cameras UniWB, keep changing your WB until your exif data in line c628 reads 1,1,1 and that is your cameras UniWB

---------- Post added 05-10-2019 at 01:55 AM ----------

I will also further add that because of this reason people think that their red channel clipping their problem as to why they see problems with red, they go about the idea of selecting a small exposure to insure that they don't have any clipping, but you have to remember most of the time its the converter cause this issue of clipping and not the size of the exposure you are using.

This will lead the user down the wrong path to getting the best out of your reds as they have now restricted how much data that they are collecting for the red channel and can cause the loss of details in the reds because of the red channel being underexposed with more noise in a channel that is already starting off as being the more noisy channel.
Forum: Pentax DSLR Discussion 05-09-2019, 01:42 AM  
How red is your red ?
Posted By Ian Stuart Forsyth
Replies: 84
Views: 4,007
A lot of the time the problems we have with red and flowers had more to do with software, more importantly the raw converters and the color space that is causing us these issues.

One of the issues is WB and how it works, what it essentially doing is multiplying one or more of the color channels more than the other to create a white balance. In daylight and shadows this can be as much as 1 or more stops for the red channels and this is a majority of the problems you see in the reds. Under most shooting conditions itís the green channel that is the first to clip and cause you issues. Here is an image with what seems like issues with clipping in the reds and what it looks like in the raw converter.


But the true is there really is no problems with clipping and itís all how the image is being converted and if we look at the real data that is not being clipped with software this is a better representation of what the raw file looks like

But if we look at the data that is contained in the raw file you will see that there is no clipping and that the green channel is the one closet to clipping and that the red is nearly 2 stops bellow clipping.

If you are wanting to utilize your camera to the best of its ability and using the cameras histogram shooting raw I would recommend learning what UniWB is, this is a way of setting up your camera so that when youíre using the cameras histogram you are doing so without this WB and multiplying of the color channels, this way you will have a better representation of how the three color channels are truly captured.
GUILLERMO LUIJK >> TUTORIALS >> UNIWB. MAKE CAMERA DISPLAY RELIABLE

Another problems is that the color space you have chosen is what is clipping your reds and any data you want to display here all I have done is change the color space to Pro Photo RGB, I have basically eliminated all my clipping in just doing this


Next I would go about learning what your raw converter is doings so behind the scenes and set it to a more real representation as to how the data is contained in the raw file. I would first find out what BLE( base line exposure) is
Where Are My Mid-tones? Deriving Hidden Baseline Exposure Compensation

For most of the pentax cameras I have used the BLE is -0.5


(While this is not a representation of a artistic rendering it is just to show the process latitude you have to start with) Here I have setup my raw converter at a better starting point for me to start my raw processing

Here is the end viewed photoshop in ProPhoto RGB



Here is the final in Prophoto RGB
Forum: Pentax Full Frame 11-10-2018, 11:33 PM  
are you happy with switching to FF?
Posted By Ian Stuart Forsyth
Replies: 310
Views: 22,588
I can clearly see what that decrease in light had on the image, one of the biggest is the increase in noise and other artifacts


Take for example this image was taken with an exposure using iso 2000 that is 1/4 the size of your Raven image exposure but it shows less of the artifacts that you can see in your image, this is what happens when you crop you decrease how much light the image is made up of






No its not the same image, here's a hint it has a narrower FOV and in doing so you increase the magnification of the artifacts found within your image, noise being one of them ;)




How can the APSC sensor use double the light ,I take it that you mean that crop body allowed twice the amount of light because of the F/5.6 is being used over that of the FF at F/8. The major problem with this thinking is that they both lenses let the same amount of light for the final image. We know this because the hole letting the light in from the lens was both are almost the same size 200/5.6= 35mm opening while the 300/8=38mm size of opening. In order to keep the same output image brightness the cropped body needed to decrease the shutter speed to maintain the output image. If one body had to decrease the shutter this should be a clear indication to you that it is made up of less light.



And why do you have to reduce your image by the means of cropping to make it 4k I would tend to think it would be better to reduce the image size by scaling and use how you have decided to frame your image at the time of capture, very strange way to use your camera ?



Upscale only magnifies the unwanted artifact that you will see in the image and in now way give you the effect of adding more light, while scaling will change the artifacts like noise and place those artifacts into a smaller area that occupies less of your final output image. To think so differently leads me to believe that you don't know the difference between the 2. again all you have to do is look at the 100% crop from your raven and the uncropped image of the raven at 4mp output and you will see exactly that a decrease in noise in the final image.




If this is your thinking and that you need to crop the most from a format to display an image on a 4 k monitor then many of the new bridge cameras will even give you better results over what you are using if we use your train of thought

It has more to do with the light and the amount that you can store in adition the additional pixels allow you to more aggressively use NR and sacrifice detail for less noise. We want more light because of how sensors capture light and anything that falls in the mid tones and lower are only capturing 1/8- 1/16 of the light in an exposure at base iso. When we factor in how the colors are captured you will find that most of the time the red channel is only using 1/32 of the sensors capacity to store light in anything that falls where our subjects fall mid tones, we also want more resolution to help combat how we capture red details and how they are limited by how the sensors work.



As shown by your crow crop you can see a difference at 4mp



Again with downsizing you are not throwing away the light you have collected you are shifting those artifacts to a resolution that is hidden to the outgoing image display resolution.

---------- Post added 11-11-2018 at 12:41 AM ----------



The f stop is 1 stop different but the aperture letting light into the image is the same, we know this by what is written on the lens
take the 300mm F/8 that is a formula for the size of the aperture 300mm/8= 38mm with the 200mm/5.6=36mm so both lenses for their given format let roughly the same amount of light but because one of the images used the shorter shutter speed and used less exposure time this should tell you that less light was captured in the final image.
Forum: Pentax Full Frame 11-07-2018, 04:51 AM  
are you happy with switching to FF?
Posted By Ian Stuart Forsyth
Replies: 310
Views: 22,588
It was a bigger deal when we only had 6, 10, 16mp with FF but as we start into the 24 and 36mp FF there is less of a dominance for wildlife and cropped bodies other than buffer and frame rate and cost but if I had to carry and use one body it would be FF.




You can already see this in 24mp cameras FF and cropped even when the FF 24mp camera has a AA filter it still with capture more resolution over a cropped camera without the filter. If we just look at the captured resolution between both 24mp cameras if we look at how much we can further crop based on captured resolution it only falls in around 1.35 crop factor and this is with a camera that employees a filter.

For me the narrow gap where a cropped 24mp camera excels at reach (iso 100-400) and in the area where diffraction really limits what you can see then what's the scene of the camera. As lenses start to fill out a lineup in the longer FL it's even less of a worry with reach . One of the arguments we see is an image showing a a K3 with 200 2.8 and a k1 and 300mm F2.8 well of coarse one setup will be heavier but if they went with the k1 and 300 F4 they are comparable in weight , DOF and FOV but one has a lot more reach over the other and all the benefits of FF. If we take a look at the reach factor between the K3 and K1 based on pixel density it falls within the 1.22 crop factor range, to put it into perspective at a working distance for small birds and a 500mm lens at 10m you would only have to setup your camera 1.5m closer for the FF camera.

---------- Post added 11-07-2018 at 06:04 AM ----------




Your meter and exposure is based on a unit of area measurement so no it will be the same. The light that the larger sensor captured when cropped will not be used so there is less light going into the image.



As it shouldn't



A very simple test you can do to see the difference in the light that you can gather between using and the whole image is to do this little test

Take you k1 something like 300mm lens and shoot it using iso 100 F8 and the shutter speed the camera selects. Then set your camera to 1.5 crop and select iso 100 and use a lens that would give you the same FOV this would be 200mm but to keep the same DOF you will need to set the lens to F5.3 then notice to happens to your shutter speed and then see what happens if you force the camera to use the same shutter speed?
Forum: Pentax Full Frame 11-07-2018, 02:01 AM  
are you happy with switching to FF?
Posted By Ian Stuart Forsyth
Replies: 310
Views: 22,588
No what I am saying is that anytime you want to decrease the how much light that you can store within the final image, If you are cropping your 24mp image to a 6mp image the cost of doing so is how much light that you have access to and the ability to store within the limits of the sensor.

There are no setting if you select to crop the image your are inadvertently limiting how much light that image will be made from.



You have cropped out the light the image sensor has captured, so the image will no longer have the same DR, color depth as you have cropped the signal that gives you those image quality's. As for cropping and resolution you loose resolution there also. Take the average lens on a 24mp sensor will give you 3600lw/ph if you are to crop that into a 6mp you are left with 1800lw/ph in the final 6mp image. You may have decreased the FOV but that comes at a cost and that is light and resolution.



That only applies if you are shutter speed limited

Only if you are shutterspeed limited will you capture the same amount of light, and even this will not be the same as you can substitute the extra detail from the K1 for more of an aggressing NR, in real world uses you can shoot your k1 at a faster shutter speed and use the additional resolution to decrease the noise level with that NR.




Nothing stops you from stopping down the FF to achieve the same DOF.




The first part of this statement tell me that you should really think about " it was too dark to get the same image with APSc or FF without a tripod" all you would have to do it shoot the other formats with the same aperture dia and shutterspeed and you could have used ether FF or cropped.


And that a good point you made about taking a look at the actual exposures of an image, so let go back to cropping and light loss and provide evidence that there is light loss.

Take a person using FF and a 600mm lens and lets say they use iso100 F8.4 1/300 sec, now if you are the a person using a aspc 24mp camera and you only use a 6mp crop that that sensor to get you to the same FOV from a 200m lens. We know that to get the same amount of light and DOF as that FF shot you would only need to use that lens at f2.8 but there is no way that you would be able to shoot that image at the same shutter speed as you would over expose your image (more light).
Lets look a the exposures again more closely 600mm iso 100 f8.4 1/300sec vs 200mm iso 100 F2.8 but to keep the same level of image lightness you would need to use a shutter speed of 1/1250sec instead of the 1/300sec, if you are using a faster shutter speed then it means less light about 1/8



It will also cost you how much light you can capture, this in turn limits your DR color depth and how clean your tonal ranges will be.


If it was only about high iso performance and shooting at wider fstops, you forget that how much light you can capture is limited to you by how much you can store before clipping.

There is no way you can use a 200mm on a 24mp apcs camera at iso 100 f8 1/300sec and hope to capture the same amount of light when using the same camera with a 100mm then cropping to 6mp to get the same FOV and the same DOF as the sensor cannot store the light the uncropped image gathered. Granted most cameras have more than enough DR to me its more about how much light I can make use of and any time you start to use a smaller image circle you limit the light you can store. This is most evident when shooting at base iso, we know this as anything that falls within the midtones is made up of 1/8 to 1/16 of the light the image sensor can store this becomes a problem.

---------- Post added 11-07-2018 at 03:05 AM ----------



You may want to reread the post you quoted, If you crop you will lose light. If cropping does not reduce the amount of light the please tell me how would you capture the same amount of light with this FF camera shot at iso 100 f8 1/200sec ?

---------- Post added 11-07-2018 at 03:06 AM ----------



Ok then use the same DOF as the above question I asked you already, use the same DOF and tell me how you would capture the same amount of light ?

---------- Post added 11-07-2018 at 03:40 AM ----------



At least 3/4 of my wildlife and landscape photograph does not require me to use the same exposure time.

If you have a surplus of light why would you sluff off much of the light you are given with more of a shutter speed than needed, while it is nice to use equivalence to compare cameras across different formats a great deal of the time you don't need to shoot equivalent to get the images in the real life.

Take this image here there was no need to shoot it at iso 200 as I could shoot it at a slow enough shutter speed even when I choose to expose it for raw



---------- Post added 11-07-2018 at 03:46 AM ----------



In real life you seldom need to shoot using an applies to applies comparison, a lot of the time we waste the light we are given with shutter speeds that are not need

K-1 or K-3 for birding - Page 2 - PentaxForums.com


You could call this a rookie mistake that I pointed out to you and all you did was insult me oh well
Forum: Pentax Full Frame 11-04-2018, 10:18 PM  
are you happy with switching to FF?
Posted By Ian Stuart Forsyth
Replies: 310
Views: 22,588
The same way using a smaller sensor , which is no different than cropping will reduce the amount of light that will be found in the image

---------- Post added 11-04-2018 at 11:33 PM ----------



How we view images has changed with the advent in the digital age, the way I now look at images is as a interactive format rather than a final print with a set print size. More or less how we used slides in the past but with the ability to pick and choose how we view the image in an interactive way.

There is also the problem of the unwanted artifacts that will plague the image when cropping too much like noise, less DR, false detail, NR, lens faults, focus error and loss of contrast. Too often times the any use to correct these artifacts will in themselves create more issues
Forum: Pentax Full Frame 11-04-2018, 04:07 AM  
are you happy with switching to FF?
Posted By Ian Stuart Forsyth
Replies: 310
Views: 22,588
Several years ago I came to a similar and realistic assessment of going full frame also. I mainly went that path for wildlife. I looked in the areas where I wanted to see the greatest benefit for what I wanted to shoot.
This realisation I soon decided that I was going to stop this idea I had that it was the camera with the greatest reach that would give me the images I was looking for. This search for a camera with the best pixel density strayed me from the path I was looking in my final images.

I soon came to the realisation that that a 6mp crop taken from 24mp did too much damage to what I was looking for from the standpoint in IQ, this idea of narrowing the FOV with pixel density is where I stopped looking and more true with the pixel density we now see. Back when we have only 6, 10 15 mp I did see some of the benefits of using pixel density as a way of narrowing my FOV.

One of the biggest hurdles I was facing when using pixel density to increase my reach was the light loss as the result of this reach through cropping. The resulting side effect of cropping was that I needed more light and I was left using the lens at its widest and/or shutter speeds not the best for the condition I was shooting in if I was concerned about noise.

A 6mp image crop from 24mp cropped camera at base iso will only give me only 1/8 the capacity to gather light as a FF camera could And to tell you the truth over the last 6 years I have found that I was better off in the decision of using a modest FL to decrease my FOV and technique for the images I am looking for.
Forum: Pentax News and Rumors 10-28-2018, 12:35 AM  
Yay! Ricoh Imaging will announce a new camera this month or next month! (Nokishita)
Posted By Ian Stuart Forsyth
Replies: 343
Views: 23,450
Most of the time we are linking our survey work through our smartphones to transfer and communicate with reference station, this is used to communicate corrections from a base station.
We always have a phone to transfer data and even photos up to a cloud base site, 99% of the time the photos are taken with the cell phone as that is how we transfer our data and is really seamless.
Forum: Pentax Full Frame 10-27-2018, 02:40 AM  
are you happy with switching to FF?
Posted By Ian Stuart Forsyth
Replies: 310
Views: 22,588
FF really has come into it own with regard to digital and more so now that Nikon and 3rd party vendors haave started to release cheaper lenses for wildlife work. You can get to 400mm for $1200 and the lenses only come in at 2.5 pounds a lot of users only need 24mp and are happy with that.

Getting to 600mm is now even cheaper than we have seen in years $1300- 2400 at 4 lb to 6 lb gives you a verity of lens options, this gives the FF shooter that uses only 24mp a lot of reach and selection and often times only supplement their system with the D500 for speed and AF and use the FF for its benefits.
Forum: Photographic Technique 10-26-2018, 08:30 PM  
Setting up K5ii in low light
Posted By Ian Stuart Forsyth
Replies: 15
Views: 1,093
The noise is created from using a higher iso because that selection in that iso causes the camera to use a smaller exposure. You have to understand that the exposure is what happen in front of the sensor scene luminosity, shutter speed and aperture. The iso is basically what happens within the sensor and the processing done for that exposure.


When selecting a higher iso you are telling the camera to use a smaller exposure and to do this it needs to develop the image differently and also shift the cameras meter for the less light that is captured because of this smaller exposure. It is this smaller exposure that causes the increase in noise ( this is do to the noise found in the very light its self shot noise) that you see when increasing the iso, the camera on the other hand generates less noise ( read noise being the most prominent) as you increase the iso and with some cameras this can be very pronounce. With the K5 you will see some decrease in read noise that it produces from iso 100-1000, going above iso 1000 does not decrease the read noise.
Forum: Photographic Technique 10-25-2018, 03:18 AM  
Setting up K5ii in low light
Posted By Ian Stuart Forsyth
Replies: 15
Views: 1,093
There is a downside as to how much light you can store in the sensor, above iso 1000 the camera really becomes isoless and increasing above that really would not give you any benefit other than showing you an image you can review on your LCD



Nothing really as of yet, it would also be nice if there was a UniWB, this way you can see how each channel saturates differently depending on the light source.

There is also the problem of findings the settings with the raw file converter that would truly show you what is contained within the raw file. If you are using abode you need t find out the baseline conversion for that camera


https://photographylife.com/where-are-my-mid-tones-baseline-exposure-compensation

There is also the problem with how WB of a camera works, what it does is apply a multiply to the different color channels of the sensor, to see how this data would look in the raw file and its histogram you would need to set the WB to a UniWB

http://www.dslrbodies.com/cameras/camera-faq/what-is-uniwb.html

combined with overriding the presets of the raw converter then you can better understand what data is found in the raw file. At this time I would recommend using something like fastrawveiwer.
This will better help you to understand what is contained with in the raw file, where the camera clips data in the raw file and how the color channels saturate under different light sources .





Raising the iso decreases the noise that the camera produces, its the decease in the exposure to accommodate the increase in iso that causes noise

http://www.photonstophotos.net/Charts/RN_e.htm#Pentax%20K-5%20IIs_14



not really if you are shooting raw, and if you are shooting raw with the k5II really shooting above iso 1000 really doesn't help you much and can cause you the greater risk of clipping data if you don't set your exposure correctly up to the clipping point.

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