the limits of zoom

cantanima bis said:

TSeiler said:

Here is a shot taken hand held with my S1 at 2400mm, that is 1200mm plus the internal doubler. I have no idea what a print would look like since I don't print anything. It is good enough for my purposes.

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Was this is taken indoors? If so, that probably doesn't include the haze, which was Tom's main point.

But: EXIF says 160.5mm focal length. Crop factor is roughly 5.5, and including "internal doubler" (?) brings equivalent focal length to 1765. How do you get 2400mm? (Not looking for an argument, just trying to figure out how this becomes 2400mm.)

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alexisgreat said:

TSeiler said:

tomhongkong said:

The maximum zoom reach of bridge cameras has become a ridiculous marketing feature, quite unrelated to the images they take.

As always it depends on your usage of the images and your expectation of quality. (And whether you are an astronomical photographer using a tripod at night, or a regular daylight shooter).

My comments are based on capturing images which print at 10x8 inch, which are adequately sharp, and which have a bit of latitude for cropping to tidy up the edges (ie the captured image is a bit bigger)

There are physical issues with the camera design, which I will come on to, but the over riding limitation is atmospheric quality. Your own shots recently of birds in a tree illustrate this. I don't want to be rude about them, but all the detail in them has gone because of haze (and probably a not very good lens as well). If you use a telephoto to get close up shots of subject which are not far away, this obviously does not apply.

Personally I doubt whether the day time atmospheric conditions in most parts of the world allow for decent distant zoom shots much above 600mm, except in unusually good weather conditions (and some night time star shots do benefit from clear air).

If someone insists on trying for longer zoom, what hardware would they need? The old rule of thumb is that exposure time should be 1/focal length. (Whilst IS systems help for static subjects, they do nothing for moving things.) This leads to wide apertures or high iso. P&S bridge cameras have small sensors and usually small apertures needing high iso (there are a few with constant f2.8 lenses which helps a bit) Small sensors and high iso don't yet go together. 35mm cameras have sensors which are better at high iso but the size of long lenses becomes enormous...see the sports photographers round a football match, and they are probably using 400mm max.

Holding long zooms steady is quite a problem, so using longer exposure times is only going to work using a tripod. You could try using a bridge camera on a tripod, iso100. with a longer shutter speed. (Don't forget to turn IS off if you use a tripod) but the lens quality is then going to be the limitation

So current technology does not allow a P&S/Bridge camera, where the lens could be physically manageable, to take good long telephoto images, and a large sensor camera is unmaneagably large at long FLs (somewhere here there is a shot of a 1000mm Sigma lens, just check it out).....never mind the astronomical cost!

I think the very best compromise for a long zoom at present is the Nikon 1 at around 800iso with a 70-300cx zoom (limited to f5.6 and the exposure that implies) With a a 2.7 multiplier this gives an equivalent zoom range of 810mm. So long as atmosphere does not spoil the shot, you can get decent feather detail of birds properly filling an image frame. (I use feather detail as a good measure of the detail of an image, not suggesting that bird photography is the only reason for using a long lens)

Of course I will be happy to be proven wrong, and look forward to seeing sample images (scaled to 2000 x 2500 pixels so that they would make an average 8x10 print) which show exactly what the current crop of superzooms can do (and how the zoom can be extended further)

Just my 2p worth

tom

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Here is a shot taken hand held with my S1 at 2400mm, that is 1200mm plus the internal doubler. I have no idea what a print would look like since I don't print anything. It is good enough for my purposes.

--
My portfolio:
https://picasaweb.google.com/108464110929132780547/MyPortfolio

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The shot looks very smooth and lacks any of the annoying mottled stuff I see in my shots even at ISO 100- did you use any software to remove the noise? Very impressive! If you have a chance please post the original as I want to see what it looks like 1:1.

--
https://supermanalexthegreat.shutterfly.com/

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tomhongkong said:

I don't want to start a war or be over critical. Everyone takes photographs to the best of their ability and to meet their own expectations. I can only suggest that we should all look at the quality of photos taken by the 'pros' and ask ourselves if we are still satisfied with our own output. I know that each time I do I end up feeling very humble.

For some examples of tele shots taken with a smallish (1") sensor, i can recommend looking at some of the posts by Thomas Stirr using a Nikon1.

I continue to strive to improve!

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TSeiler said:

I just got back from lunch. I took my camera and took a few shots. It is hard to find subject matter at 2400mm and it is hard to hand hold and get the subject in the middle of the frame. All the shots are right out of the camera with no post processing at all. You can look at the full size images and judge for yourself. I was going to shoot them in RAW but I forgot that you can't shoot RAW and use the doubler at the same time.

http://s466.photobucket.com/user/seilerbird/library/2400mm

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alexisgreat said:

alexisgreat said:

...

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One thing I've been trying to get an answer to concerning superzoom lenses, there are some so-called "experts" who claim that the "effective focal length" increase is only a perceived benefit, that the real resolution of these lenses is no more than what the "actual" focal length of the lens would be had it been used on a 35mm camera. In other words, the resolution of the HS50 lens is no more at maximum zoom than what an 185mm lens on a 35mm format camera would be. They say that the only difference is that you are cropping from that when you attach that lens to a smaller sensored camera and any "enlargement" is the result of post process effects on the computer or when you print out.

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alexisgreat said:

Small sensors run into problems with lens diffraction, which limits image resolution at small apertures-- starting around f/16 for the 35mm format. At large apertures-- f/4 and above-- resolution is limited by aberrations. There is a resolution "sweet spot" between the two limits, typically between f/5.6 and f/11 for good 35mm lenses. The aperture at which a lens becomes diffraction-limited is proportional to the format size: 22 mm diagonal sensors become diffraction-limited at f/8 and 11 mm diagonal sensors become diffraction-limited at f/4-- the same aperture where it becomes aberration-limited. There is little "sweet spot;" the total image resolution at optimum aperture is less than for larger formats. Of course cameras with small sensors can be made very compact, which is attractive to consumers.

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alexisgreat said:

Do I Really Need To Know This Stuff?

Actually, yes, you do. Pay attention. It’s important

You especially do if you’re one of those photographers who enjoys thinking about, reading about and talking about lens sharpness. The reason is that the wordsharpnessis vague and can mean different things at different times to different people. MTF on the other hand is the terminology that lens designers use, and which you need to come to terms with if you really want to understand how to describe the complex interaction between resolution and contrast.

For the optical designer contrast and resolution are in conflict. Increase one and you reduce the other. Various lens makers have differing philosophies in the regard. Historically, for example, Zeiss was reputed to design their lenses for maximum resolution, while Leica apparently tended to favour maximum contrast. It is design decisions like these that account in part for the differing “looks” of different lens brands.

...

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Understanding MTF Charts

Understanding MTF Charts - Luminous Landscape

luminous-landscape.com

alexisgreat said:

DigitUnderstanding image sharpness part 1:
Introduction to resolution and MTF curves
by Norman Koren

A photograph's detail is an integral part of its appeal. Many photographers spend a great deal of time, energy and money acquiring equipment to make sharp images. Back in the film era, if 35mm didn't satisfy them, they invested in medium format, 4x5, 8x10, or larger. (I know two who use 8x20 inch cameras.) The digital versus film debate is now mostly settled (2007), but there is still some debate over the relationship between the number of megapixels and image quality. I love sharpness and detail, but I take my camera gear on long hikes, so I prefer to carry lightweight equipment. I need to know what it can achieve, how to get the most out of it and what I'm trading off by not going to a larger format, apart from saving my back. That's what motivated this study.

The sharpness of a photographic imaging system or of a component of the system (lens, film, image sensor, scanner, enlarging lens, etc.) is characterized by a parameter called Modulation Transfer Function (MTF), also known as spatial frequency response. We present a unique visual explanation of MTF and how it relates to image quality. A sample is shown on the right. The top is a target composed of bands of increasing spatial frequency, representing 2 to 200 line pairs per mm (lp/mm) on the image plane. Below you can see the cumulative effects of the lens, film, lens+film, scanner and sharpening algorithm, based on accurate computer models derived from published data. If this interests you, read on. It gets a little technical, but I try hard to keep it readable.

...

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TSeiler said:

tomhongkong said:

I don't want to start a war or be over critical. Everyone takes photographs to the best of their ability and to meet their own expectations. I can only suggest that we should all look at the quality of photos taken by the 'pros' and ask ourselves if we are still satisfied with our own output. I know that each time I do I end up feeling very humble.

For some examples of tele shots taken with a smallish (1") sensor, i can recommend looking at some of the posts by Thomas Stirr using a Nikon1.

I continue to strive to improve!

Click to expand...

I could give a crap less about anyone else's 'quality'. I am happy with my photos. Those were not meant to be works of art, they were intended to show off the quality at 2400mm. Nothing more nothing less. I am so sorry I tried to do you a favor.

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photoreddi said:

alexisgreat said:

photoreddi said:

...

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One thing I've been trying to get an answer to concerning superzoom lenses, there are some so-called "experts" who claim that the "effective focal length" increase is only a perceived benefit, that the real resolution of these lenses is no more than what the "actual" focal length of the lens would be had it been used on a 35mm camera. In other words, the resolution of the HS50 lens is no more at maximum zoom than what an 185mm lens on a 35mm format camera would be. They say that the only difference is that you are cropping from that when you attach that lens to a smaller sensored camera and any "enlargement" is the result of post process effects on the computer or when you print out.

Click to expand...

By saying "so-called 'experts'" you seem to have doubts about the "experts'" expertise and that indicates that you have good instincts and don't think that their opinions pass the sniff test.

They're mistaken in many ways and don't understand how complicated a subject 'resolution' actually is. But first using your example let's compare like with like. Compare the 16mp HS50 at 185mm (1000mm equivalent fl) with a 185mm lens on a Nikon 16mp full frame camera (Df or D4). At those focal lengths the fields of view are completely different and photos taken by the HS50 won't look anything like photos shot with the D4, so to make a proper comparison where the compositions are the same you'd have to use a central crop of the D4's image to be able to compare images with the same fields of view.

The HS50 has a crop factor of somewhat less than 5.45 (see http://www.dpreview.com/forums/post/51150828 ). So the D4's sensor has a surface area that's more than 29 times larger than the HS50, about 29.5x if you average the two values from that link. So if you crop away most of the D4's image, retaining only the central 1/29th portion of the image, both cameras will show similar scenes. But now you're comparing a 16mp HS50 image versus a similar D4 image that's using only 0.542 megapixels (16/29.5). I doubt that anyone seriously thinks that you get higher resolution from a 0.542mp crop of a full frame camera than a full 16mp image from a superzoom camera.

The EXR sensor complicates resolution comparisons but you could do the same math using a Nikon P510/P520/P530 which also has a 16mp sensor but it's slightly smaller so it has a 5.6x crop factor.

Now we get to trying to make sense of resolution. Sensors have resolutions and so do lenses, but lens resolutions vary with the focal lengths, the apertures used and the contrast of what is being photographed. Do you recall when I tested Fuji's cameras and found that they produced the highest resolution at maximum focal length when the aperture was wide open at f/5.6? In looking through several articles describing resolution and MTF I found one of Norman Koren's articles that explained why :

photoreddi said:

Small sensors run into problems with lens diffraction, which limits image resolution at small apertures-- starting around f/16 for the 35mm format. At large apertures-- f/4 and above-- resolution is limited by aberrations. There is a resolution "sweet spot" between the two limits, typically between f/5.6 and f/11 for good 35mm lenses. The aperture at which a lens becomes diffraction-limited is proportional to the format size: 22 mm diagonal sensors become diffraction-limited at f/8 and 11 mm diagonal sensors become diffraction-limited at f/4-- the same aperture where it becomes aberration-limited. There is little "sweet spot;" the total image resolution at optimum aperture is less than for larger formats. Of course cameras with small sensors can be made very compact, which is attractive to consumers.

Click to expand...

Many small sensor cameras (SX50HS, P520, P610, P900) have 1/2.3" sensors and according to DPReview's Sensor Size glossary article, they have an 11.044mm diagonal. The HS50's slightly larger sensor has a 12.7mm diagonal so for all practical purposes it's also diffraction limited at about f/4.

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photoreddi said:

http://www.dpreview.com/glossary/camera-system/sensor-sizes

.

If you're interested, Luminous Landscape has a relatively non-tech/math free article and Norman Koren's are heavier going but he says that he tries to keep it from getting too technical, but this will depend on the reader.

photoreddi said:

Do I Really Need To Know This Stuff?

Actually, yes, you do. Pay attention. It’s important

You especially do if you’re one of those photographers who enjoys thinking about, reading about and talking about lens sharpness. The reason is that the wordsharpnessis vague and can mean different things at different times to different people. MTF on the other hand is the terminology that lens designers use, and which you need to come to terms with if you really want to understand how to describe the complex interaction between resolution and contrast.

For the optical designer contrast and resolution are in conflict. Increase one and you reduce the other. Various lens makers have differing philosophies in the regard. Historically, for example, Zeiss was reputed to design their lenses for maximum resolution, while Leica apparently tended to favour maximum contrast. It is design decisions like these that account in part for the differing “looks” of different lens brands.

...

Click to expand...

https://luminous-landscape.com/mtf/

.

Norman Koren's article is the first of a set and near the top are links to the other articles in the set.

photoreddi said:

DigitUnderstanding image sharpness part 1:
Introduction to resolution and MTF curves
by Norman Koren

A photograph's detail is an integral part of its appeal. Many photographers spend a great deal of time, energy and money acquiring equipment to make sharp images. Back in the film era, if 35mm didn't satisfy them, they invested in medium format, 4x5, 8x10, or larger. (I know two who use 8x20 inch cameras.) The digital versus film debate is now mostly settled (2007), but there is still some debate over the relationship between the number of megapixels and image quality. I love sharpness and detail, but I take my camera gear on long hikes, so I prefer to carry lightweight equipment. I need to know what it can achieve, how to get the most out of it and what I'm trading off by not going to a larger format, apart from saving my back. That's what motivated this study.

The sharpness of a photographic imaging system or of a component of the system (lens, film, image sensor, scanner, enlarging lens, etc.) is characterized by a parameter called Modulation Transfer Function (MTF), also known as spatial frequency response. We present a unique visual explanation of MTF and how it relates to image quality. A sample is shown on the right. The top is a target composed of bands of increasing spatial frequency, representing 2 to 200 line pairs per mm (lp/mm) on the image plane. Below you can see the cumulative effects of the lens, film, lens+film, scanner and sharpening algorithm, based on accurate computer models derived from published data. If this interests you, read on. It gets a little technical, but I try hard to keep it readable.

...

Click to expand...

http://www.normankoren.com/Tutorials/MTF.html

Click to expand...

alexisgreat said:

TSeiler said:

I just got back from lunch. I took my camera and took a few shots. It is hard to find subject matter at 2400mm and it is hard to hand hold and get the subject in the middle of the frame. All the shots are right out of the camera with no post processing at all. You can look at the full size images and judge for yourself. I was going to shoot them in RAW but I forgot that you can't shoot RAW and use the doubler at the same time.

http://s466.photobucket.com/user/seilerbird/library/2400mm

Click to expand...

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alexisgreat said:

alexisgreat said:

...

Many small sensor cameras (SX50HS, P520, P610, P900) have 1/2.3" sensors and according to DPReview's Sensor Size glossary article, they have an 11.044mm diagonal. The HS50's slightly larger sensor has a 12.7mm diagonal so for all practical purposes it's also diffraction limited at about f/4.

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Thanks PR, I'm going research all of this, but one thing I needed to ask you is that dont 1/2 format sensors have 8mm diagonals? the 1/2 inch (or 12.7mm) is the diameter of the cathode ray tubes used back in the 50s.

alexisgreat said:

http://www.dpreview.com/glossary/camera-system/sensor-sizes

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alexisgreat said:

"Dia." refers to the diameter of the tube size (this is simply the Type converted to millimeters), "Diagonal / Width / Height" are the dimensions of the sensors image producing area.

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photoreddi said:

alexisgreat said:

photoreddi said:

...

Many small sensor cameras (SX50HS, P520, P610, P900) have 1/2.3" sensors and according to DPReview's Sensor Size glossary article, they have an 11.044mm diagonal. The HS50's slightly larger sensor has a 12.7mm diagonal so for all practical purposes it's also diffraction limited at about f/4.

Click to expand...

Thanks PR, I'm going research all of this, but one thing I needed to ask you is that dont 1/2 format sensors have 8mm diagonals? the 1/2 inch (or 12.7mm) is the diameter of the cathode ray tubes used back in the 50s.

photoreddi said:

http://www.dpreview.com/glossary/camera-system/sensor-sizes

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Good catch. If you check the sensor size glossary article you'll see that as you say, the 1/2" sensor diagonal is 8mm. I was looking in the wrong column, the one that specifie the diameter, not the diagonal, and just above the table it says :

photoreddi said:

"Dia." refers to the diameter of the tube size (this is simply the Type converted to millimeters), "Diagonal / Width / Height" are the dimensions of the sensors image producing area.

Click to expand...

.

That's unfortunate since the small sensor cameras aren't really diffraction limited at f/4. Since the diagonal is even smaller than the sensors Norman Koren was speaking about it, Fuji's small sensor cameras might be diffraction limited at about f/2.8 instead.

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TSeiler said:

If you look at any of the images in the upper right hand corner you will see five icons. The one with the + inside the magnifying glass will take you to the original size. You are welcome. I was using 1/1000th to reduce shake.

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alexisgreat said:

PR, you didn't answer my question from the last post but I just thought of another.

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alexisgreat said:

So let's say we have a 1" sensor with 16 MP. We can divide that 1" sensor into four 1/2" sensors with 4 MP each. Does this mean that a 1/2" sensor with 4 MP will produce the same image quality as a single 1" sensor with 16 MP?

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alexisgreat said:

I know the resolution will be lower, but shouldn't a single 1/2" sensor with 4 MP produce quality like that of a 16 MP 1" sensor cropped into four equal parts of 4 MP each? I think not- but I'd like to know why- I'm thinking that imae quality is dependent on the size of the sensor as well as its pixel pitch- in short, when it comes to sensor size, the whole is greater than the sum of the parts.

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alexisgreat said:

Orion would love to see a 4 MP 1/2" sensor since you could still have a very portable megazoom lens even up to 3000mm at f/8, but for the reasons above I dont think it would approach the image quality of a 16 MP 1" sensor. In addition when we downsample a 16 MP 1/2" sensor we improve perceived sharpness and lower noise levels.

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alexisgreat said:

I still miss the cleanness of the ISO 100 images of my 3-7 MP 1/1.8 sensor cameras.

--
https://supermanalexthegreat.shutterfly.com/

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photoreddi said:

alexisgreat said:

PR, you didn't answer my question from the last post but I just thought of another.

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I intended to reply, the reply is even open in a tab somewhere. Is that the one where you had a link to the Adobe article about producing vastly improved noise performance by combining 40 photos? I haven't been able to respond very much since my computer died a couple of days ago. I'm now using and old 32-bit XP laptop with less than 3GB of usable RAM that couldn't be used until I reformatted the drive and reinstalled WinXP using the installation DVDs that I created many years ago. Page Up and Page Down keys no longer near the cursor keys and USB2 instead of USB3. Ugh.

System Properties shows that the computer has an Intel Core2 Duo T8100 CPU @ 2.10Ghz with 2.99 GB of RAM. With the help of others in the Computer forum about a week ago I got links to download service packs 2 and 3. Microsoft's normal web pages made it seem like they were no longer available. I had intended to create a dual boot system with Windows and Linux, but the Windows reinstallation software on a hidden partition that would have created a smaller Windows partition crashed, so I had to use the installation DVDs, that they forced the partition to use all of the disk space.

.

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photoreddi said:

photoreddi said:

So let's say we have a 1" sensor with 16 MP. We can divide that 1" sensor into four 1/2" sensors with 4 MP each. Does this mean that a 1/2" sensor with 4 MP will produce the same image quality as a single 1" sensor with 16 MP?

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I guess so, but if you make prints from both sensors such that the same image quality is the same, the ones made from the 1/2" sensor images would necessarily be 1/4 the size. Print them the same size and the ones made using the 1" sensor will have better image quality and about a one stop better DR and high ISO noise performance due to the larger sensor area.

.

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photoreddi said:

photoreddi said:

I know the resolution will be lower, but shouldn't a single 1/2" sensor with 4 MP produce quality like that of a 16 MP 1" sensor cropped into four equal parts of 4 MP each? I think not- but I'd like to know why- I'm thinking that imae quality is dependent on the size of the sensor as well as its pixel pitch- in short, when it comes to sensor size, the whole is greater than the sum of the parts.

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You need to look more closely at the size of the sensor/film. Old MF and LF cameras had amazing image quality but it had less to do with the film technology (grain size as a substitute for sensor tech/pixel pitch) than the huge image recording area. Have you ever seen 8"x10" film contact prints?

.

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photoreddi said:

photoreddi said:

Orion would love to see a 4 MP 1/2" sensor since you could still have a very portable megazoom lens even up to 3000mm at f/8, but for the reasons above I dont think it would approach the image quality of a 16 MP 1" sensor. In addition when we downsample a 16 MP 1/2" sensor we improve perceived sharpness and lower noise levels.

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He only seemed to be able to get similarly decent image quality from his S(mall) size moon photos, and I think that the reason was because of the leveling effects of seeing conditions and elevation that prevented L(arge) photos from doing any better. For photos of subjects that aren't so far from the camera, L and M size photos should always look better than S size photos if you look close enough.

.

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photoreddi said:

photoreddi said:

I still miss the cleanness of the ISO 100 images of my 3-7 MP 1/1.8 sensor cameras.

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