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02-09-2022, 08:49 PM - 1 Like   #31
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QuoteOriginally posted by fuzzyphotos Quote
Well, I spent the day examining the Nikon options, never thought I would do that. I still need to decide if that is something I want to do but sounds more reasonable after researching a little. A D810 in crop mode gets me the same (almost) field of view as on the pentax crop but I loose a few mega pixles off shooting a K5. The D7500 would likely be the best Nikon option. I have information overload on Nikon right now so may be wrong on that point.


The Mississippi is a little more narrow where we were, about 2000 feet wide. I told a friend I had never seen so many eagles in one place and she went over there. The eagles were on the same side as she was, so I need to go back. I know 600mm won't help with the cross river shots but would help getting them when they are fishing in the middle or closer.
BEFORE YOU SPEND MONEY...

Read this site about long lens use in Yellowstone:
https://www.pointsinfocus.com/travel/yellowstone-tetons/camera-gear-for-yell...national-park/

Pay attention to the distance vs. frame coverage numbers for various game.

Subject Focal Length % of frame filled Subject Distance
Black Bear 600 mm 80% 100 ft.
Black Bear 600 mm 50% 167 ft.
Brown Bear 600 mm 80% 120 ft.
Brown Bear 600 mm 50% 214 ft.

An eagle will be tiny at 1000' even with a 600mm lens on a crop body (these numbers are with Full Frame I think)

---------- Post added 02-09-22 at 10:51 PM ----------

Also the Nikon adapter shown earlier is a bad quality teleconverter - don't do it. Use Nikon directly on the Pentax mount but bear in mind this does not lock unless you make a lock indent in an appropriate spot. Nikon lenses (manual ones) can be used directly on a Pentax mount but it isn't very secure.

02-09-2022, 09:16 PM - 1 Like   #32
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QuoteOriginally posted by UncleVanya Quote
BEFORE YOU SPEND MONEY...

Read this site about long lens use in Yellowstone:
https://www.pointsinfocus.com/travel/yellowstone-tetons/camera-gear-for-yell...national-park/

Pay attention to the distance vs. frame coverage numbers for various game.

Subject Focal Length % of frame filled Subject Distance
Black Bear 600 mm 80% 100 ft.
Black Bear 600 mm 50% 167 ft.
Brown Bear 600 mm 80% 120 ft.
Brown Bear 600 mm 50% 214 ft.

An eagle will be tiny at 1000' even with a 600mm lens on a crop body (these numbers are with Full Frame I think)

---------- Post added 02-09-22 at 10:51 PM ----------

Also the Nikon adapter shown earlier is a bad quality teleconverter - don't do it. Use Nikon directly on the Pentax mount but bear in mind this does not lock unless you make a lock indent in an appropriate spot. Nikon lenses (manual ones) can be used directly on a Pentax mount but it isn't very secure.
I posted some pics using that adapter a few dsys ago that showed it to be better than its reputation had me believe.

F-mount (Nikon) to K-Mount (Pentax) and visa versa - PentaxForums.com

I am not advocating it but I think its better than I thought it would be .I have more trials to do on it. I would not recommend the op get it as the lens needs an Aperture ring which leaves out alot of newer lenses and theres alot of better options.. I got it to try because I was curious .

I do have to caution though that using a nikon lens directly on a pentax body may be okay for a light and small lens, doing so with a long lens may be asking for an accidental drop of either the camera or the lens.. jmo
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02-09-2022, 09:31 PM   #33
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QuoteOriginally posted by fuzzyphotos Quote
Well, I spent the day examining the Nikon options, never thought I would do that. I still need to decide if that is something I want to do but sounds more reasonable after researching a little. A D810 in crop mode gets me the same (almost) field of view as on the pentax crop but I loose a few mega pixles off shooting a K5. The D7500 would likely be the best Nikon option.
If you look at pixel density and the amount of pixels you are able to put on your subject

For the D7500/D500 using a 600mm lens and with the cropped factor you are working with 20mp with a FOV that is 900mm
For a FF 36mp camera using the same number of 20mp you are able to crop to a FOV that is 800mm
If you are using a 24mp cropped camera using the same 600mm lens you are able to put 24mp with a FOV 900mm
If you are using a FF and crop to 24mp so that you are putting 24mp on your subject you have a FOV that is 730mm

So in reality you are only dealing with a crop factor of 1.23 or less between a FF36mp and a 24mp cropped camera

Last edited by Ian Stuart Forsyth; 02-09-2022 at 09:37 PM.
02-09-2022, 11:24 PM   #34
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QuoteOriginally posted by Ian Stuart Forsyth Quote
If you look at pixel density and the amount of pixels you are able to put on your subject

For the D7500/D500 using a 600mm lens and with the cropped factor you are working with 20mp with a FOV that is 900mm
For a FF 36mp camera using the same number of 20mp you are able to crop to a FOV that is 800mm
If you are using a 24mp cropped camera using the same 600mm lens you are able to put 24mp with a FOV 900mm
If you are using a FF and crop to 24mp so that you are putting 24mp on your subject you have a FOV that is 730mm

So in reality you are only dealing with a crop factor of 1.23 or less between a FF36mp and a 24mp cropped camera
Iím going to ask you show how you came to these numbers. Your assertions just arenít making sense in my head. I typically look at this the other way - how big is the bird on the sensor. And then, how many pixels are on that area. In bird photography, Iím rarely not cropping past the apsc image frame. So it really doesnít matter if I can crop 24mp from 36 at a particular ratio. What matters is that if I crop to apsc I only have 15mp. This is about 1.6x lower density of pixels than a 24mp apsc sensor has. Assuming my subject and framing elements fills half of the 16x24mm area thereís 7.5mp in one image and 12mp in the other. Thatís a 1.6x crop factor.

02-10-2022, 12:47 AM   #35
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QuoteOriginally posted by UncleVanya Quote
I’m going to ask you show how you came to these numbers. Your assertions just aren’t making sense in my head. I typically look at this the other way - how big is the bird on the sensor. And then, how many pixels are on that area. In bird photography, I’m rarely not cropping past the apsc image frame. So it really doesn’t matter if I can crop 24mp from 36 at a particular ratio. What matters is that if I crop to apsc I only have 15mp. This is about 1.6x lower density of pixels than a 24mp apsc sensor has. Assuming my subject and framing elements fills half of the 16x24mm area there’s 7.5mp in one image and 12mp in the other. That’s a 1.6x crop factor.
If we first look at your 12mp compared to 7.5mp that is not a 1.6 crop factor it is 1.26crop factor, you have to look at it in 2 dimensions, For example 36mp camera cropped by a factor of 1.5 is not 36 / 1.5 as that would give you a a final pixel count of 24mp

we have to take into account that 36mp has both height and width so 1.5 x 1.5 = 2.25 so 36mp / 2.25 = 16mp

Now lets go back to the 12mp compared to 7.5mp 12 / 7.5mp= 1.6 √2= 1.265 crop factor
So a 12mp camera with a 300m will have an additional crop ability of 1.265 giving you an image that is 7.5mp with a FOV that is 380mm and not the 480mm FOV when using that 1.6

Now with a FF 36mp camera if you are cropping down to a 24mp image you are only cropping by 36/24=1.5√2=1.22 and not below the level of an apsc

So a FF36mp cropped to 24mp will give you a crop factor of 1.22 with a 600mm lens you would have a FOV 730mm
A 24mp cropped camera with a 1.5 crop factor will give you a 24mp image with the FOV 900mm
You have to also remember because you are enlarging the 24mp 1.5 cropped image more to be viewed as the same size as the larger 24mp 1.22 cropped image there will be some resolution loss due to this enlarging

A very simple way to look at it is if you want to double your lenses reach (600mm-1200mm) you need to quadruple you pixel count by place 4 times more pixels into the same area

With a 36mp camera I seldom go below a 1.2 crop and that is only for shooting raw for buffer and frame rate

Last edited by Ian Stuart Forsyth; 02-10-2022 at 01:04 AM.
02-10-2022, 01:34 AM   #36
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If you are someone who constantly practices photographic hunting, I advise you to make a sacrifice and buy a good lens with apochromatic lenses and good brightness, but if you make few outings you can "settle" for a mirror lens that, with little expense, will give you a lot of satisfaction.
02-10-2022, 04:04 AM - 1 Like   #37
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QuoteOriginally posted by UncleVanya Quote
BEFORE YOU SPEND MONEY...

Read this site about long lens use in Yellowstone:
https://www.pointsinfocus.com/travel/yellowstone-tetons/camera-gear-for-yell...national-park/

Pay attention to the distance vs. frame coverage numbers for various game.

Subject Focal Length % of frame filled Subject Distance
Black Bear 600 mm 80% 100 ft.
Black Bear 600 mm 50% 167 ft.
Brown Bear 600 mm 80% 120 ft.
Brown Bear 600 mm 50% 214 ft.

An eagle will be tiny at 1000' even with a 600mm lens on a crop body (these numbers are with Full Frame I think)

---------- Post added 02-09-22 at 10:51 PM ----------

.
+1

I prefer to simply use math

Subject size = image size x focal length / distance

02-10-2022, 06:58 AM - 2 Likes   #38
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QuoteOriginally posted by Ian Stuart Forsyth Quote
If we first look at your 12mp compared to 7.5mp that is not a 1.6 crop factor it is 1.26crop factor, you have to look at it in 2 dimensions, For example 36mp camera cropped by a factor of 1.5 is not 36 / 1.5 as that would give you a a final pixel count of 24mp

we have to take into account that 36mp has both height and width so 1.5 x 1.5 = 2.25 so 36mp / 2.25 = 16mp

Now lets go back to the 12mp compared to 7.5mp 12 / 7.5mp= 1.6 √2= 1.265 crop factor
So a 12mp camera with a 300m will have an additional crop ability of 1.265 giving you an image that is 7.5mp with a FOV that is 380mm and not the 480mm FOV when using that 1.6

Now with a FF 36mp camera if you are cropping down to a 24mp image you are only cropping by 36/24=1.5√2=1.22 and not below the level of an apsc

So a FF36mp cropped to 24mp will give you a crop factor of 1.22 with a 600mm lens you would have a FOV 730mm
A 24mp cropped camera with a 1.5 crop factor will give you a 24mp image with the FOV 900mm
You have to also remember because you are enlarging the 24mp 1.5 cropped image more to be viewed as the same size as the larger 24mp 1.22 cropped image there will be some resolution loss due to this enlarging

A very simple way to look at it is if you want to double your lenses reach (600mm-1200mm) you need to quadruple you pixel count by place 4 times more pixels into the same area

With a 36mp camera I seldom go below a 1.2 crop and that is only for shooting raw for buffer and frame rate
Based on this set up.


And these two images




I'm estimating in the real world, the magnification of the K-3 and the exact same set up an position, the real world advantage is about 36%. Someone cooking a bunch of numbers means nothing to me. This is what's real.

SO, to get the same image I could be 36% further away with APS-c, a real benefit for birding. As for the total noise thing and worse noise on APS-c. Ya slightly worse. But not meaningfully worse. These images haven't been run through Topaz Denoise. It's a safe bet that once it has, the noise will be the same. The K-1 however will never recover the missing detail. And there's not enough difference to make any kind of case anyway, unless you were making the case that there is virtually no benefit based solely on total light.

Any attempts to describe this difference have to come up with the "right answer" or they shouldn't be entertained.

With all due respect to the above, the difference is significant any way you look at it. The numbers are just numbers. The proof is in the pudding. The biggest problem with the math, as demonstrated here is, you make one little mistake and you create falsehood. Without confirmation in the real world it's useless.

This is why a notion is just a notion until supported by empirical data. Then it may become a hypothesis and eventually a theory. What I'v posted represents real world usage, not some convoluted math worked out to try and prove some kind of a point that makes no sense in the real world.

But then I'm not using arbitrary crops that I would never use in real life to try and prove a point. That's the thing about mathematical proofs, you can demonstrate something that might be mathematically true, that is practically irrelevant. But you still need to get your numbers right, confirming with real world shooting, hopefully, before you post the information.

The measured lw/ph of a k-5 is ~2100. The measured lw/ph of a k-3 is ~2700. Nothing you can do with the K-1 images cropped will make up for the extra 600 lw/ph in the FF mode. That 600 lw/ph is just gone, no matter how you crop it. And 600 is significant, unlike many 100 lw/ph differences.

The crop factor, APS_c to FF is 1.5, no matter how you stack it. 600mm FF is the same field of view as 400mm on APS-c, and there is more pixels on the subject (and therefore more resolution) where the pixels are smaller on APS-c, which is the true until you get to really expensive 51 or higher MP FFs.

Last edited by normhead; 02-10-2022 at 12:30 PM.
02-10-2022, 06:50 PM   #39
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I am pleasantly surprised by the quality of photos from a Sigma 170-500 DG APO I received today. Far better than I expected it to be as the full zoom 500mm. Definitely worth consideration. Images attached both with and without 1.4 and 1.7Pentax TC's. I didn't get a chance to try the lens until it was very late in the day and the light had started to fall. I'll get more interesting pics tomorrow, including my eagle nesting on the cell tower since I know that is an interest of yours. With any luck his fledgling will be exercising his wings, he's not yet flown.

First image is a 100% crop of the second taken at 500mm. Third is at 700mm with a 1.4TC, and the fourth is at 850mm with the Pentax 1.7AF. Note that the EXIF gets confused by the combo. The last two are at 700mm and a 100% crop of it.
Attached Images
View Picture EXIF
PENTAX K-3 Mark III  Photo 
View Picture EXIF
PENTAX K-3 Mark III  Photo 
View Picture EXIF
PENTAX K-3 Mark III  Photo 
View Picture EXIF
PENTAX K-3 Mark III  Photo 
View Picture EXIF
PENTAX K-3 Mark III  Photo 
View Picture EXIF
PENTAX K-3 Mark III  Photo 

Last edited by gatorguy; 02-10-2022 at 06:57 PM.
02-10-2022, 08:37 PM   #40
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There is so much good information here, thanks to everyone that's responded to this. I've looked and searched and looked some more. I almost came to the conclusion to buy a Nikon D810 and the 200-500. They both get rave reviews and can be had used for under $2000 for the pair. I could put my FA*80-200 on the K5 and use the Nikon for the longer shot. Maybe I should consider the D7500 Crop sensor too. I have a couple items watched on evil bay with a few days to go. HOWEVER, just as I was typing this it occurred to me, what if for now, I got the Pentax af 1.7 adapter? That gets me to 510mm, granted its a little slower and then I could decide if 500mm was long enough. If not, maybe I get a 645 A*600mm and the adapter to PK mount. I see them around the $2000 price as well. Still not sure the 150-450 gains me anything over the current 420 I have with the 1.4 TC. Well, I guess it does get me to 630mm but at about F7 with the TC. So I ramble on about options, and really there are options. A D810 was what I was thinking about back when I decided to stay with Pentax.


So, after all that, let me ask this question, have any of you used the 1.7 AF adapter on the DA* 300mm F4? were the results reasonable?

Thanks for putting up with my indecision! or tightwaddness


Tim
02-11-2022, 12:08 AM   #41
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QuoteOriginally posted by normhead Quote
I'm estimating in the real world, the magnification of the K-3 and the exact same set up an position, the real world advantage is about 36%.
Instead of using your real world estimation lets use testing under lab conditions from you favorite site. All resolution charts at exported to 24mp and under these conditions please tell me how much do you see, sure there is some but detail not as much as you seem to think
Care to take a guess as to which is the K5Ii or the K3II and to make things fun there is a 20mp FF camera added



https://photos.smugmug.com/Temp/Temp/i-Pkb7tj2/0/ec570311/O/question.jpg

A B or C what is the 24mp cropped camera, what is the 16mp cropped and what is the 20 mp FF ?




QuoteOriginally posted by normhead Quote
SO, to get the same image I could be 36% further away with APS-c, a real benefit for birding. As for the total noise thing and worse noise on APS-c. Ya slightly worse. But not meaningfully worse. These images haven't been run through Topaz Denoise. It's a safe bet that once it has, the noise will be the same. The K-1 however will never recover the missing detail. And there's not enough difference to make any kind of case anyway, unless you were making the case that there is virtually no benefit based solely on total light.
No, it has to do with trying to make an image with a lens that is 300mm FL into an image with a narrower FOV cropping with pixel density and then comparing it to a image taken with a lens that is using a much larger area of that lenses image circle. there is a cost in doing so.

QuoteOriginally posted by normhead Quote
But then I'm not using arbitrary crops that I would never use in real life to try and prove a point. That's the thing about mathematical proofs, you can demonstrate something that might be mathematically true, that is practically irrelevant. But you still need to get your numbers right, confirming with real world shooting, hopefully, before you post the information.
I have test several lenses from $9000 to $3600 that has told me that I cannot make a 300mm lens with a images FOV equal to a 600mm lens with out any costs and that cost is a decrease in the resolution you are able to record.

Even some of the sharpest lenses on thee market when using 1.4 converter or cropping the IQ can fall into the realm of mid to higher end zooms.

Here is an image taken at 600mm with a 24mp crop



https://photos.smugmug.com/Temp/Temp/i-4qwZTk9/0/74cba939/O/croppeddd.jpg



https://photos.smugmug.com/Temp/Temp/i-Bcqq5RD/0/e193cb3f/O/cppre.jpg

Nothing beats reach thru FL and the size of the image circle recording the image

The measured lw/ph of a k-5 is ~2100. The measured lw/ph of a k-3 is ~2700 I am kind of interested where this data comes from
02-11-2022, 12:54 AM   #42
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QuoteOriginally posted by biz-engineer Quote
Good , high quality wildlife shots of birds require to be within 4 to 20 meter distance from the subject , depending on the size of the subject. Getting close, shooting from a hide, that's the secret of making good wildlife images.
If the subject is across the river, you need 2000mm or more. Use a bridge camera Nikon P1000 or buy a T-mount to K mount adapter to mount your camera on a scope.
Here's an example of a superzoom bridge camera vs DSLR:

Cameras are Canon SX50hs (12MP @ 1200mm FF-equiv., f6.5) and Pentax K-3 (24MP with Tamron's 70-300mm f4-5.6 @ 300mm, 450mm FF-equiv., f8).

The Canon is on the left - a lightly sharpened image from Raw; the K-3 is an in-camera jpeg (probably set to fine sharpening), and both images are of course crops:
Attached Images
 
02-11-2022, 04:25 AM   #43
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QuoteOriginally posted by m42man Quote
The Canon is on the left - a lightly sharpened image from Raw; the K-3 is an in-camera jpeg (probably set to fine sharpening), and both images are of course crops:
I don't see much difference. The problem of using a large sensor camera and heavy cropping is that it's a waste of sensor area and bad use of lens image circle (and larger lens). If it's to crop, better use a camera system with a smaller sensor, less expensive and lighter weight.
02-11-2022, 04:51 AM   #44
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QuoteOriginally posted by biz-engineer Quote
I don't see much difference.
You're just joking around with the OP, right?

Of course the difference is obvious, and the Canon image was even sharpened a bit and still mud detail on the amplifier and the pole behind the dish. Had both been shot RAW (like the Canon) simply pull up the shadows on the K3 and voila. FAR better with the K3 crop.

Last edited by gatorguy; 02-11-2022 at 04:59 AM.
02-11-2022, 04:54 AM   #45
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QuoteOriginally posted by biz-engineer Quote
I don't see much difference. The problem of using a large sensor camera and heavy cropping is that it's a waste of sensor area and bad use of lens image circle (and larger lens). If it's to crop, better use a camera system with a smaller sensor, less expensive and lighter weight.
Well, I think I'd agree. Though, if you already own a decent DSLR, maybe the cost of a long lens vs a superzoom camera becomes relevant.

The superzoom has the advantages of far less bulk, plus the ability to stabilise the frame seen through the EVF - which facilitates accurate focussing on the intended subject. Though use of a stabilised lens with the DSLR would have the same advantage...

---------- Post added 11th Feb 2022 at 12:10 PM ----------

QuoteOriginally posted by gatorguy Quote
You're just joking around with the OP, right?

Of course the difference is obvious, and the Canon image was even sharpened a bit and still mud detail on the amplifier. I didn't even have my glasses on when I first glanced at it. I do now tho.
Do note that sharpening a Raw image is standard practice where an AA filter has been employed. Plus, the K-3 will have sharpened its Raw image to provide the jpeg output.

The Canon's sensor is truly tiny (1/2.3"), compared with the K-3's APSC - and would need good lighting to be able to offer any competition in terms of noise (at similar apertures). Also, though the Tamron is stellar value for money, there are better-performing long lenses available (at a price!). But I think the K-3 crop is slightly superior, regardless.

For me, it comes down to bulk and viewfinder stabilisation, I suppose. (Not that I use long focal lengths much anyway.)
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