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Food Shutter Bug Club (Part 2)


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107 replies to this topic

#31 dcarch

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Posted 05 January 2012 - 05:33 PM

Great photos Prawncracker (the food ain't bad either LOL).

When selecting a camera, besides everything else, you need to consider focal length of the lens system. Professionals use long focal length to get that natural look. You can't get better perspective using wideangles.

For instance, one is more natural looking:

dcarch

Posted Image

Posted Image

#32 Prawncrackers

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Posted 05 January 2012 - 05:52 PM

You've got a very keen eye and great techinical knowledge dcarch, I would never have realised the distortion of that picture. To me it's a tin of petit fours but to the photographically trained eye it's wonky!

#33 Prawncrackers

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Posted 05 January 2012 - 05:58 PM

Dakki I really don't have any ground breaking insight i'm afraid, i'm a happy snapper like you. Just keep your hand still and squeeze that shutter gently!

#34 Dakki

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Posted 05 January 2012 - 06:02 PM

Pretend you're talking to a Martian who's never seen a camera before. What do you get with the longer focal length? Can you get a longer focal length using optical zoom? Will that have other effects (such as, exaggerating camera shake)?
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#35 dcarch

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Posted 05 January 2012 - 06:11 PM

Pretend you're talking to a Martian who's never seen a camera before. What do you get with the longer focal length? Can you get a longer focal length using optical zoom? Will that have other effects (such as, exaggerating camera shake)?


Short focal length (wideangle) lens has what's known as Spherical aberation, or, wine barrel effect. You never use wide angle lens for potraits. You end up with pictures of gigantic noses.

Long focal length lenses will require a tripod, or spend $10,000 for a very fast lens.

dcarch

Edited by dcarch, 05 January 2012 - 06:13 PM.


#36 Dakki

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Posted 05 January 2012 - 06:18 PM

Aha!

What's a good length to start at? Does it vary by lens? Would you expect to see this spherical aberration in a lens installed on a pocket camera or are we talking about specialized lenses for DSLR's here?
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#37 Dakki

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Posted 05 January 2012 - 06:19 PM

And, could you get around that by shooting a wider pic and then cropping the edges?
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#38 C. sapidus

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Posted 05 January 2012 - 06:23 PM

Pretend you're talking to a Martian who's never seen a camera before. What do you get with the longer focal length?

Welcome to our planet, I hope you come in peace. :wink: Longer focal lengths will “flatten” the picture and yield narrower depth of field (less of the picture in focus). dcarch and prawncrackers give good examples of these effects. For more, see perspective distortion (photography) at Wikipedia.

Can you get a longer focal length using optical zoom?

Yes

Will that have other effects (such as, exaggerating camera shake)?

Yes. Get a beanbag, set it on a solid object (upside-down pot?), and rest the camera on the beanbag. That should eliminate camera shake.

Edit: drat, y'all type way faster than I do. Shouldn't have stopped to help elder son with his college essay . . .

Edited by C. sapidus, 05 January 2012 - 06:25 PM.


#39 dcarch

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Posted 05 January 2012 - 06:27 PM

There are no rules. A SLR camera allows you to play with different lenses.

with computer designed aspheric lenses and better glasses of index of refraction, they are doing better to minimize distrotions. For food photos, a perspective correcting lenses can be useful, but they don't make that kind of lenses much anymore.

dcarch

#40 Dakki

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Posted 05 January 2012 - 06:28 PM

Thanks, C. sapidus. I think I'll spare your puny planet, for now.

Is there any way to get that flat, narrow DOF besides using a longer length of focus, such as manipulating aperture and/or shutter speed?
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#41 SobaAddict70

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Posted 05 January 2012 - 06:33 PM

Pretend you're talking to a Martian who's never seen a camera before. What do you get with the longer focal length? Can you get a longer focal length using optical zoom? Will that have other effects (such as, exaggerating camera shake)?



a tip, from someone who does not use a tripod...

when you hold your camera, form two sturdy supports on the bottom of the camera with your thumbs, similar to that of an inverted "V".

obviously this technique isn't for everyone. in my experience, it eliminated the "shake" effect completely.

#42 dcarch

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Posted 05 January 2012 - 06:38 PM

The shakes!

Press the camera tight against you forehead, Set the camera on self-timer. Takes longer (3 seconds on mine) almost completely eliminate shaking.

dcarch

#43 dcarch

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Posted 05 January 2012 - 06:41 PM

Thanks, C. sapidus. I think I'll spare your puny planet, for now.

Is there any way to get that flat, narrow DOF besides using a longer length of focus, such as manipulating aperture and/or shutter speed?


Short answer, no.

A very small aperture (old pin hole camera) can eliminate some spherical distortion.

dcarch

#44 Dakki

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Posted 05 January 2012 - 06:58 PM

Lots of good info here. Thanks, guys. (And keep it coming if you have any more!)
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#45 C. sapidus

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Posted 05 January 2012 - 07:07 PM

More than you ever wanted to know about depth of field from DOF master (click)

Edited to add:

Short version: Long focal length + wide aperture = narrow depth of field.

Edited by C. sapidus, 05 January 2012 - 07:18 PM.


#46 Blether

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Posted 05 January 2012 - 10:22 PM

Yes, wider apertures give a shallower depth-of-field (and of course you have to use a faster shutter speed to go with them).

I can't believe there's not more love for tripods, at least in the home kitchen: dcarch, your suggestion of self-timer is a good one. Another tip is to drink 30 less beers the night before :shock:

With an SLR now, Dakki, you've the chance of using bounced flash - buy a flash unit with a head that swivels between straight-forward and straight-up, and work out how to set the aperture in various situations (trial and error for your particular kitchen, say). Some of the folks round here who produce exceptional photos are using bounced flash regularly. You also now have the option of multiple flashes (wired together or with the 'slave' sensors that are common now), if you want to get into serious studio-type photography. 2/3 of the light from above and to one side; 1/3 from the other side; a little backlighting for depth.

It's still a trusim that when real expert phtographers talk about equipment, it's about their preference for tripod mounting head.

Edited by Blether, 05 January 2012 - 10:25 PM.

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#47 Dakki

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Posted 05 January 2012 - 10:32 PM

Er, SLR? I think I must've misposted: this is what I got. I didn't pay that much for it, though.

I did get a little toy tripod to go with it.
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#48 Blether

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Posted 05 January 2012 - 10:33 PM

... What's a good length to start at? Does it vary by lens? ...


You won't normally go shorter than a normal lens (50mm length in the 35mm SLR format) for food photography. I'd say a portrait lens or just a bit longer (80-100mm) is as long as you'll need to go to cover more than 90% of your needs here. A zoom lens covers all the lens lengths from its minimum to its maximum (so for example a 28mm-105mm zoom would be a good starting place). The trade-off with zoom lenses is that (at maximum aperture) they let in less light than 'prime' (single-length) lenses. So you might see a 28-105mm lens with an aperture range f22 - f3.5; but a fixed 50mm lens f22-f1.4.

A macro facility (lets you get real close and real detailed) is also an asset in shooting food.

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#49 Blether

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Posted 05 January 2012 - 10:35 PM

Er, SLR? I think I must've misposted: this is what I got...


Hahahaha. Hmm. Scratch all that.

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#50 Dakki

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Posted 05 January 2012 - 10:42 PM

It's good to know this stuff anyway. Thanks.
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#51 Dakki

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Posted 05 January 2012 - 11:00 PM

The reason I'm asking about apertures and lens speeds and so on is that this camera has manual controls for those things on the body. That's the reason I retired the old one.

I really don't want to get into the whole buying-a-whole-bunch-of-lenses-and-filters-and-whatnot-and-getting-married-to-a-brand thing, and even the old camera was a bit too bulky for me anyway. Of the pocket-sized ones with manual controls this one apparently has the better low light performance, as well as being rather less expensive. (I ended up blowing the putative savings on spare battery, cards, etc. anyway).
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

#52 ChefCrash

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Posted 05 January 2012 - 11:11 PM


Thanks, C. sapidus. I think I'll spare your puny planet, for now.

Is there any way to get that flat, narrow DOF besides using a longer length of focus, such as manipulating aperture and/or shutter speed?


If by "narrow DOF" you mean shallow dof like this:
PC042227-2.jpg

It's tough to achieve with a small sensor camera. But can easily be done in post using Photoshop. This works best with photos taken at low angles. Here is Sobaaddict's photo:
6541692139_1582d68c4d_o.jpg

This is how it looks after one minute in Photoshop:

6541692139_1582d68c4de_o.jpg



Open your photo in PS. Click on the layers menu and choose "duplicate layer". In the dialogue box click "ok".

Untitled-1.jpg

Click on the filters menu and choose "Gaussian Blur". In the dialogue box choose a number between 5 and 20. Click "ok".

Untitled-2.jpg



Create a mask by clicking on the square icon with the small circle in the middle, at the bottom of the Layers pallet.
Choose the "Gradient Fill tool". Place the pointer at the tip of the piece of fish in the foreground (bottom of image), click and drag a straight line to the top of the image. That's it. If you don't like the effect, just undo and place the pointer in a different spot, click and drag up to the top again.

Untitled-3.jpg

#53 dcarch

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Posted 06 January 2012 - 05:50 AM

The nicest thing about taking good photos for a non-professional is CFL bulbs.

You don't need $1,000 1,000 watt studio lights that only last a few hours and that would also BBQ your food while you are taking pictures.

BTW, slave flashes (very cheap)are actually wireless, a very good suggestion.

Tripod tip:

Get one that will allow you to reverse the center post (camera mount) up side down, so that you can take top views of your dish. Not all tripods can do that. This may also make it nice to have a camera with an articulated view screen.

dcarch



#54 David A. Goldfarb

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Posted 06 January 2012 - 07:49 AM

Short DOF without Photoshop isn't actually that difficult with the subject distances used in food photography, even with APS format (small sensor) cameras, and it tends to look more natural than Gaussian blur. Just select a wide aperture (low f:stop number), and you will narrow the focus range of the image.

Depth of field is generally a function of the f:stop (wider aperture, less DOF), subject distance (closer for less DOF), and the focal length of the lens (longer for less DOF), and sensor/film size. In the macro range (magnification of 1:10, image size on the sensor:actual size of the subject), DOF is effectively a function of aperture and magnification alone, regardless of focal length, setting aside the issue of format size for the moment.

(You don't have to worry about the role of the format size too much, but it's one of the things that most people who think they understand DOF tend not to get. DOF is always understood with respect to an average size print at a normal viewing distance for that size, not with respect to the image projected on the sensor/film, so if you wanted to calculate the DOF range for a given subject distance and aperture, you would have to plug in a somewhat subjective value for the "acceptable circle of confusion" for the sensor/film format, and sometimes the usually accepted value is inadequate for a given task--i.e., you might need more DOF than the calculated aperture gives you, so you might stop down a little more for more DOF.)

Here are some photos from my flickr stream made with an APS-C format camera (Canon 40D). Most food photos, most using selective focus (short DOF), no Photoshop blur or tilt/shift lens tricks on these--

http://www.flickr.co...gs/canoneos40d/

Edited by David A. Goldfarb, 06 January 2012 - 07:50 AM.


#55 Blether

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Posted 06 January 2012 - 07:58 AM

... Here are some photos...


That bramble & custard tart is a beauty, food & image both.

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#56 David A. Goldfarb

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Posted 06 January 2012 - 08:13 AM

with computer designed aspheric lenses and better glasses of index of refraction, they are doing better to minimize distrotions. For food photos, a perspective correcting lenses can be useful, but they don't make that kind of lenses much anymore.

dcarch


Actually, there are more perspective control (tilt/shift) lenses available for SLRs now than there have ever been. Canon used to make only the 35mm TS, and now they make them in 17mm, 24mm, 45mm, and 90mm, and there are offerings from Nikon and Schneider, and you can even get Hasselblad medium format lenses on tilt/shift mounts for 35mm and smaller format cameras. I have two of the Canon T/S lenses, mostly for architectural photography, but occasionally I use them for food, and I also have a sliding mount that lets me put my Canon DSLR on the back of a view camera with very extensive camera movements, or I can just use film in a view camera and scan the result. This adds a lot of complexity to the process, and there are many ways of making good food photographs without perspective control.

These lenses let you control the shape of objects in the frame and to control the plane of focus. So if you have to photograph a tall building that you want to appear square in the photograph instead of trapezoidal, you can level the camera so the building appears square and raise the lens so the whole building fits into the frame, within limits. Or if you are photographing a plate of food and you want the whole thing in focus, but you don't want to do an overhead shot, and you can't get it all in focus by stopping down to a smaller aperture, you can tilt the lens to get the whole plate in focus. You can do this, because of the Scheimpflug rule--the film/sensor plane, the lens plane, and the plane of focus all meet in a line, unless they are parallel (which would normally be the case with a lens that doesn't tilt).

Tilt/shift lenses are more expensive, larger, heavier, and slower (smaller maximum aperture), than lenses that don't have movements. Most people don't need them for most kinds of photography.

#57 David A. Goldfarb

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Posted 06 January 2012 - 08:18 AM


... Here are some photos...


That bramble & custard tart is a beauty, food & image both.


Thanks. The hardest thing with those is to get the edges of the shortbread crust to stand up so it looks good in the photograph, without cutting back on the butter or using a higher protein flour, so it still tastes like a good shortbread crust.

#58 ChefCrash

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Posted 06 January 2012 - 10:20 AM

Short DOF without Photoshop isn't actually that difficult with the subject distances used in food photography, even with APS format (small sensor) .....

......


APS is not small, with a crop factor of~1.5 versus Dakki's 1/2" sensor with a crop factor of~5.5.

#59 David A. Goldfarb

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Posted 06 January 2012 - 10:47 AM

Thanks, I missed the link up there in Dakki's post. That is way smaller, but I still think of anything smaller than 35mm full frame (which itself small, thinking historically), as "small sensor" by today's standards.

So that's going to make short DOF even harder to do, but not impossible. If you can control the aperture, select a wide aperture, and get as close as you can to the subject. It's hard to do, if you can't focus manually, or at least select the focus point.

As far as a tripod goes, I always use a tripod for food shots, unless I'm just getting a casual snapshot in a restaurant while I'm eating. I even have a tripod mount for my iPhone.

#60 Dakki

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Posted 06 January 2012 - 11:20 AM

Thanks for all the advice, guys.

How critical do you think is the shallow DOF for decent food photos?
This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.