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2020-08-22

The Crop Factor vs. Increased Magnification Problem



I encountered a problem when listening to TheSnapChick:
https://www.youtube.com/watch?v=UJQOmvX9fgs
at 1:46 min.
where she (approximately) said that "if you take a photo of this guy with full format camera he looks like this (him in whole figure) but when you change the camera to a Nikon D500 (DX type) he'll look like this (image showing the upper body of guy, apparently closer up).

Fantastic! I thought.
Just minutes later I checked at Scandinavian Photo:
https://www.scandinavianphoto.se/nikon/af-s-nikkor-200-500mm-f56e-ed-vr-1020842
selling this lens and one of their selling arguments was "corresponds to 750mm at a DX-type camera".

Aha, I thought TheSnapCick was right!

But, but, but... Problem: Does it really work like that??

Well, it doesn't!
This is what's happening:
The upper image corresponds to a full frame camera, the lower to the DX-type camera
Moving the lens to the DX the field view angle get smaller and as a result, only part of the guy to the left can be seen in the smaller chip. Looking at this image,camera in hand, it looks like the magnification has increased.
It hasn't!

The upper part from photographyelement.com and the lower the same, modified by me!

I'd say both TheSnapCick and Scandinavian Photo (depending on what they mean with 'corresponds to') were wrong. (UPDATE 2020-09-14  Not! There seems to be a knowledge gap between a group of knowledgeable users and those not so knowledgeable. The former seems to know the difference between those two cases and feel it's OK to use an expression like "corresponds to 750mm at a DX-type camera" (I don't agree), some of the latter think the lesser view angle means magnification. I've got clarifying answers from both Scandinavian Photo and TheSnapChick on this subject.)

If one looks at the image of chip sizes it's like this:
The image data in the red square (Nikon D500 (DX type) is exactly the same as (in the same area) in the full frame (blue square), no smaller, no bigger.  This will be the case independently of the pixel density of the smaller chip, the field view angle stays the same (smaller) and that's what creates this apparent increase in magnification when presented on a screen in full-screen mode















Lastly: I enjoy TheSnapChick's YouTube videos enough to enlist on her courses, I need to learn more about photography and she knows a lot.

UPDATE:
The best complete lesson of the interplay between the different factors to take into consideration when it comes to decide how lenses work (and eventually which to choose) is this one:
https://www.youtube.com/watch?v=f5zN6NVx-hY
When trying to understand complexities, it can help to watch problems described in more than one way. Tony Northrup has made another one concerning the same subjects:
https://www.youtube.com/watch?v=DtDotqLx6nA
These guys have done a range of useful Youtube videos, it's worth wile to check them out!

2020-08-17

Photography, Birds in Flight ; Musings

 Taking pictures of flying birds, what camera do I need? I wan't a better one than the one I have, that's what!

History
I have had a number of single-lens reflex (SLR) cameras, Canon X and Practica Y etc. Then came the Canon Powershot Z with 3x optical zoom lens. The only thing irritating me all the time using it was the useless zoom factor. I decided that the next camera should be one with as much zoom as possible.
In 2011 I bought a used Canon SX20, went to Norway photographing birds. It was a good camera but the birds were still too far away.
Next a Fujifilm FinePix HS30EXR with manual 30x zoom. It hard a really hard time to focus when using all that zoom. It's menus was a terrible mess, the *manual* zoom was OK since, when you go birding, it was always max zoom :0). Luckily, I fell on a concrete quay and dropped the camera so effectively that it bounced several times and the lens and house separated in two. In the bin with it!
The "real" super zoom cameras were starting to appear but since I was tired of the underwhelming results in low light I decided to buy a Panasonic Lumix FZ1000, 16x, 1" chip, hoping the better photographic quality would compensate for the smaller zoom range.
It didn't.

Today
I then bought a Lumix FX82, 50x, 1/2.3" sensor as a complement and as time went buy, this camera was the one I brought with me almost always.The FZ1000 was sturdy built, much faster in all respects and image quality was better but still it was in the bookshelf back home.
As of now I'm trying to find some camera that could combine the best features in the FZ1000 with the zoom factor of the FZ82.
It doesn't exist.

Modestly (?), I'd like a camera with at 1" chip (bigger is hardly possible in this context), at least 40x magnification (roughly what up till now means 800 mm lens), at least 4k video. The industry has decided to stop at Sony Cyber-shot RX10 IV. 600 mm (~25x) lens is not enough, 800 mm is an absolute minimum. Otherwise this camera seems to have it all:







UPDATE 20220129: I did finally buy the Sony RX10 IV, 600mm, 1". It was sooo heavy, soooo expensive but it was possible to use as a replacement. In fact, my FZ82 is not used any more. There were other advantages that made me switch. It didn't work with the Lumix FZ1000, 400mm, 1" camera but this seems to the trick!
END UPDATE


Why isn't  600 mm enough? Perhaps I'm just lazy, taking photos from my garden chair?
The picture below would not be possible to take with 600 mm, that's why. From ~80 m this was taken at sunset with the FZ82. It's post processed and meant to be shown at max 50% actual size as an illustration on the web.



Just to give an idea of what "~80 m" means in reality...












I tried another approach. I looked among the MicroFourThirds, no zoom there for me. I looked at the best cameras for flying bird images (FBIs :). I looked everywhere!

To get a feeling for the inherent problems
in the birding camera context, first have a look at the top performers but don't forget to check some of the price tags! Remember that you also have to buy the lens!! Also remember, you have to carry it around, looking a bit nerdy. (Still they got these pictures with at most 600 mm lenses! Cropping and post processing? Did they have a hideout to come close?) :
https://mirrorlesscomparison.com/best/mirrorless-cameras-for-birds-in-flight/

and then, for the other end of the spectrum, on this extremely competent review of the Nikon P1000 125x 3000 mm by TheSnapChick. Especially notice the physical size difference and weight difference betwenn this Nikon and my Lumix FZ82...
https://www.youtube.com/watch?v=GTriM0c1Zsk

It's a difference you will remember every time you take the Nikon P1000 with you!
Conclusion:
It looks like the industry:
1) thinks the superzooms are toys, they don't think these photographers aren't serious ( They mean: If you are, why don't you buy a REAL camera). I think there is a lot that could be done to make using these cameras a better experience.
2) still are not producing the performance I'd like to see them do, and I'm convinced will come in a year or couple of years. (An afterthought... we'll see.)
My search for some camera I'm willing to try is on hold, I will just have to wait and see...

When waiting
There is, however something one can do to make the catching the fast flying birds on film easier (using 1200 mm lens). Buy a red (green is better) dot sight from AliBaba and put it into the flash hot- shoe, (~$25!). This will enable you to follow the birds with both you eyes open, that means that when the bird flies out of the sight, you can still see with your other eye were it went! Invaluable, I promise!

UPDATE 20220129: 
experience shows, you must glue the sight to the camera to keep setup stable. It sounds like madness but it won't destroy any of the camera's functionality. I used bondic to glue it to the closed flash. Now eveyrthing works perfectly and i can trust my setup when going out.
END UPDATE

To illustrate, this is what you see:




By the way: Do NOT buy Olympus miserable construction, It wiggles, it's worthless!

THE END!

2020-08-16

So you have a rotten window, mullioned, to fix. How hard can it be?

Update: when done reading, this may be of interest: 

Well not so. It depends on your wallet and/or your propensity to follow your own misconceptions to the (bitter?) end. I'm a self taught amateur so don't trust everything (anything?) I write!

So, let's check what I (you?) need to make a mullioned window.

1) search on the web for "table saw"
2) search on the web for "tool router"
3) search on the web for "cordless brushless drill/driver"
4) angle hook, 45 and 90 degrees, and calipers
5) Waterproof polyurethane glue (comparatively expensive but very good)

Now, this is not the only and final solution. If you have some extra space in your garage, you can replace "cheap" hand tools with old used tools, weighing hundreds of pounds, manufactured of cast iron, worthy of old gentlemen with seemingly inbred carpenter knowledge of how to make joints and other strange and complicated things.

Well, that's up to you. I don't have the space, I commute between two properties with different needs, I  need to move tools from one place to another together with other day to day baggage in our car so things have to be small and movable. So my (not necessarily yours!) choices were:






NOTE: Links are not guranteed to last, if not, search for the model names of the components)

These are the main tools. needed are also router bits from Cobolt™ (VERY good catalog!), 
60/80 teeth saw blade for the table saw, spiral drills etc.
The approximate sum is $1600. If you're making a single window it's an eyewatering cost. But, it may be that you're the owner of a house with more than one window. Also, if you learn how to make a window, there's not many other things you can't fix. Chairs, tables, hard to close/open doors, stairs etc. won't be impossible projects. Then you can spread the cost over many more items fixed.

I know a woodworking teacher. He told me he had pupils that didn't have the ability to imagine objects in 3D. It's a real problem when creating 3D objects, by hand or by a 3D printer. I am a typical case of this disability and I think that I've made every possible mistake, feeling like an idiot every time.

I do not think this will stop me. Mistakes are the founding of experience. Taking notes during the process will enable me to avoid these stupidities again.

In this case the windows consist of two parts, one inner and one outer window. The outer windows are split into four glasses separated by mullions. I had to take in account the construction of the inner windows when making the outer windows. Normally the outer windows are affected by weather, mould and rot. 

The problems I had to master are the corners of the window frame and the mullion joints to the frame and the look of things compared to what design is already was present.
Mullions facing indoors is routed like this (Thanks: the Cobolt™ catalog):


Just eye candy. There are contra profile router bits (One make a "he" profile,the other the "she one. $70 for the pair!) approximately this pattern but the mullions are 32mm thick and the shafts of the router bits for my overhand router (the Makita) are so short that this is no option (using my router table) due to the fact that the contra profile to the one in the image is too high above the router table surface. Otherwise the contra profile would have been used making one cut at the end of the mullion, precisely matching the one on the frame, saving a lot of work.

Now, to overcome this, you can make a jig and with the right ball bearing on the tool you ought to be able to crate the contra profile routing holding the router in your hands. (This is an afterthought, didn't hit me until much later when a friend asked my I didn't do it that way. Sometimes, I'm that stupid.)

I had to machine the mullions like the image and then cut the ends to a V-shape (the "he"-part) and make a cut in the window frame with a corresponding V-shape (the "she" part) to join them. Both were made by hand on my table saw (the Bosch GTS-10-XC). This is a tricky operation and took a lot of time to be able to make acceptable joints. Joints of the same type was made where the mullions crossed.
Under my conditions, I had to train before I attempted 'production'. 
This example show the first window I made. I was more successful doing the next one. Training takes tries!



To countersink the hinges into the window frame. I made a template of 5 mm aluminium. 
It was a scrap bit I got from a metal workshop. 
The owner asked me if I wanted it cut to a certain dimension. I said "no, 
the present dimension is perfect, I just found in in a heap in the shop". 
"gimme (the equivalent of) a $" he  said. 
"Sorry I have no less than twice that amount in my pocket. Is that OK with you?". It was, I 
left, both were happy :0). 

That piece is now my store of aluminium, I take a piece from it now and then, when I need to. 
Not everything will cost you a fortune.

You can see it in the image below together with my router and a set of brass template adapters from Banggood in India for a couple of bucks. The router was modified somewhat to accommodate the round sliding plate (I't forgot the right router adapter at the other house, 750 km from this site. Arrrgh!).



Routing by hand with the template, the result is displayed in the next image.



I made the windows corners the simplest way possible, sawed each part to half the original  thickness and then laid one on top of the other with polyurethane glue in between. That glue is water resistant but not for use under water for long periods of time. It's very effective, you smear it on wet (sprinkle a little water on surfaces) wood, align the pieces and clamp them together. You have fifteen minutes to do it.

When it starts to harden, it swells and fills every crevice and leaks out of the joint. 
The excess is later removed with a knife. The glue is extremely effective, fast, waterproof but poisonous both for you and the environment so use it in ventilated areas and dispose of it responsibly.

The next image shows the clamping setup. Note the band clamp around the whole window frame.
Nice tool! Just google for "band clamp" and you will find it. The orange bottle is the glue used,
this one made by Casco. Around $14,  but worth it!


Choosing tools, buying them, learning to use them, deciding how to make the window and finally doing it took me two years of spare time. I did only metal work before, welding etc. To suddenly work with an imprecise material like wood (ugh! :) took a lot of time and I did many other things during this period. Still from the time I decided I just had to learn the window business till the moment when I had one I made myself, took two years. I'm a little surprised at my own stubbornness, in fact.

Well, I had a lot of fun and having the tools, I made a lot of quick fixes in other places because it was so much easier than before.