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Old Jan 4, 2005, 12:01 PM   #1
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Hi, I'm about to change my digital camera. I've looked at the Digital Rebel EOS for a long time but now there are some others non-SLR models that seems to be better. I currently own a Kodak DC4800 that served me well but It's really difficult to shoot portraits because of the 28mm lens distorsion and several others issues. Would it really make a difference for me to have a digital SLR? Would something else, like the Canon Powershot Pro1, do the job? I also want to adapt external flashes.

Another one: If I zoom a little to correspond to a 35mm, will the distortion disappear?

Thanks!
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Old Jan 4, 2005, 12:29 PM   #2
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Portrates are normally done with lenses in the 50-80mm range. Not that effects your distortion, but I thought I'd through that out there (there are, of course, few rules in photography and what there are you can break in the right situations.)

You can buy better lenses for SLRs than they made in cameras with fixes lenses. You can spend more money in one lens than in an entire digicam! So right there, if you're really determined to get really good portrates you can spend your money on a good portrate lens and you should get better results.

There are downsides though. Cost is an obvious one. Size and weight is another. SLRs and lenses are often bigger than digicams.

You might find the interface on the SLR not too your liking. This is a personal thing, of course, but don't over look it. Go to a store and handle the camera. Take some pictures with it. I dislike the interface of the DRebel and wouldn't buy it myself. Of course it wasn't out when I got my 10D (now replaced with the 20D) but still... I dislike the compromises they made between it and the 10D.

You might see the distortion go away at 35mm. This should be easy to test. Tape a news paper to the wall, light it very brightly. Set the camera to the fstop you normally use and take a few pictures at different focal lengths. And look for distortion of the text.

Eric
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Old Jan 4, 2005, 5:16 PM   #3
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So, would there be a big difference between a portrait with a zoomed 28mm to achieve 50mm and a true 50mm objective? I know that there will be less light entering the objective with a zoomed 28mm. Maybe I could find an adaptor from 28mm to 50mm?
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Old Jan 4, 2005, 6:57 PM   #4
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Although I don't see it mentioned in the specifications anywhere, based on the size of the CCD sensor and the 35mm equivalent focal length of your lens, I can tell you that the actual focallength of the lens on your DC4800 is approximatly 5.7mm at it's wide angle end, and approximately 17.2mm at full zoom. Since the sensor is muchsmaller than 35mm film, you have a 4.875x focal length multiplier with your model.

This gives you a 35mm equivalent focal length (same angle of view you'd have on a 35mm film camera) of 28mm at the wide angle setting, increasing up to 84mm at the maximum zoom setting.

What distortion are you talking about? At it's wide angle setting, your lens has around 1.1% barrel distortion. This is what can make the edges appear bowed out some (hence the name barrel distortion, since the photo can look like a barrel when there is a lot of barrel distortion present).

At full zoom (equivalent to 84mmon a 35mm camera), your lens has no measurable distortion, based on reviews I've seen --- no barrel distortion, and no pincushion distortion.

Now, you've got other types of distortion that can occur, too. One thing to remember is that perspective changes based on your distance to subject.

So, if you're using a shorter focal length (or less zoom with your Kodak), where you'll need to be closer to your subject to "fill the frame", then it can impact facial features, etc.For example, a nose can look larger than it should compared to the face/ears behind it.

So, shooting fromfurther away using more zoom is desirable for portraits. That's why eric s. mentioned that portraits are normally done at longer focal lengths than the wide angle lens setting on your camera (which is equivalent to 28mm).

So, by simply usingzoom, you'd be using a longer focal length. This would have the impact of reducing any barrel distortion, as well as giving you a more desirable perspective for portraits.

There are other issues as well... For example, Depth of Field. This is the amount of the image that is in focus as you get further away from your focus point. Depth of Field is based on the actual (versus 35mm equivalent) focal length of the lens, focus distance, and aperture.

Since the lens on a non-DSLR model uses a much shorter focal length for any given 35mm equivalent focal length, you have much greater depth of field (more of the image in focus) for any given aperture setting and focus distance compared to a 35mm camera.

For some subject types, this is desirable. For portraits, you may want a shallower depth of field (less of the image in focus as you get further away from your focus point). So, a DSLR model can be more desirable for this use (since you can more easily blur the background with a larger aperture setting to help your subject stand out from it).

With a DSLR model, you still have a "crop factor" (a.k.a., focal length multiplier). In other words, a shorter focal length lens can be used for any 35mm equivalent focal length. But, this factor is only 1.5x for the Nikon DSLR models (50mm actual focal length would have a 35mm equivalent focal length of 75mm on a D70). So, depth of field is much shallower for any given aperture setting compared to a non-DSLR camera -- making it easier to blur backgrounds for portraits using a lens with a larger available aperture.

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Old Jan 4, 2005, 7:54 PM   #5
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I've mistaken distorsion and perspective. I don't have any distortion, but perspective problems when I shoot peoples. Also, when I'm inside, it's very easy to get blurred pictures and the colors and the exposure are rarely what I expected. Even worse, I can't see the final result using the viewfinder.

I think 3 1/2 years of evolution will make a big difference on these problems, and using a longer focal lenght with solve my perspective problem. I would have to put a lot of money to blur backgrounds and increase depth of field, and it's not a job but simply a hobby among some others.

Well, I really think I would be better with a more recent non-SLR camera for now. I will have a lot to learn with a new camera, modeling lights, umbrellas, reflectors etc...

Am I wrong saying that you can get some pretty portraits with a Canon Powershot Pro1 and some equipment?
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Old Jan 4, 2005, 8:14 PM   #6
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grouminou wrote:
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I've mistaken distorsion and perspective. I don't have any distortion, but perspective problems when I shoot peoples. Also, when I'm inside, it's very easy to get blurred pictures and the colors and the exposure are rarely what I expected. Even worse, I can't see the final result using the viewfinder.
If you're not usingthe flash, I would expect blurry photos. This is because the shutter speeds will be too slow to prevent it in typical indoor lighting.

If you want to take photos of people indoors without a flash, you'll need a model that has a bright lens (larger available aperture settings, represented by smaller f/stop numbers), as well as the ability to shoot at higher ISO speeds with relatively low noise.

A DSLR model with a bright lens is the recommended solution for existing light photos. They have much larger sensors, and can shoot at higher ISO speeds with lower noise compared to the consumer models. Most newer consumer models will have objectionabe noise levels at anything much above ISO 100. This is not high enough to allow fast enough shutter speeds indoors without a flash for non-stationary subjects with the lenses you'll find on them.

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I think 3 1/2 years of evolution will make a big difference on these problems, and using a longer focal lenght with solve my perspective problem.
You can use a longer focal length already. Just use some zoom.

As far as motion blur (which you'll get unless you increase ISO speeds),I suspect that the8 Megapixel Prosumer Models will have higher noise levels compared to your Kodak. This is because they are packing a lot of pixels into a relatively small sensor. As a result, the photosites for each pixel are smaller and unable to gather as much light. This means that they require more amplfication of their signal for equivalent ISO speed sensitivity.

If you can't use a flash, your best bet is a DSLR. If you can use a flash, then most models will work fine (preferrably one with an external flash).

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I would have to put a lot of money to blur backgrounds and increase depth of field, and it's not a job but simply a hobby among some others.
To blur backgrounds, you want to decrease Depth of Field. A lens with a larger available aperture (represented by a smaller f/stop number) is desirable. If you're on a budget and decide to go with a DSLR, I'd just get a 50mm f/1.8 lens to start out with (in addition to a "walk around" zoom lens). You can get a 50mm f/1.8 lens for under $100.00 for either Canon or Nikon DSLR models.

Quote:
Am I wrong saying that you can get some pretty portraits with a Canon Powershot Pro1 and some equipment?
You can get some pretty portraits with most cameras - - given the right lighting.

You won't be able to easily blur backgrounds, or use higher ISO speeds without objectionable noise levels. Of course, your use of the photos, desired print sizes, etc., also comes into play, and it's not necessary to blur backgrounds to get a nice looking photo (although it can help your subject to stand out from distracting backgrounds). Simply pick your backgrounds more carefully if using a non-DSLR model like the Pro 1 (or your Kodak).

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Old Jan 6, 2005, 4:56 AM   #7
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grouminou,

I am becoming frustrated at the moment. I am looking for something between a good SLR vs pocket size digital camera that takes good shots.

I am currently caught between two models; Canon PowerShot Pro 1 and Olympus C-8080.

The Olympus gets good reviews but I am leaning more towards the Canon because it is smaller and lighter.

Rgds

Yokozuna

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Old Jan 6, 2005, 8:46 AM   #8
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Well, my current issue is that my old Kodak DC4800 takes pictures in a 3:2 ratio, which is excellent since the goal is to print on a 4x6 media, but all the newer models have a 4:3 ratio which correspond to nothing but the screen... Only the DSLR I've checked, the Powershot Pro1, have the correct ratio, I really don't get it...
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Old Jan 6, 2005, 9:12 AM   #9
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grouminou wrote:
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Well, my current issue is that my old Kodak DC4800 takes pictures in a 3:2 ratio, which is excellent since the goal is to print on a 4x6 media, but all the newer models have a 4:3 ratio which correspond to nothing but the screen...
Non-DSLR models have standardized on CCD sensors that use a 4:3 Aspect Ratio, whereas DSLR Models use the same Aspect Ratio as 35mm Film.

A 3:2 Aspect Ratio is perfect for 4x6" Print Sizes, but is not as good for other sizes.

More Cropping will be required for larger print sizes using a model with a 3:2 Aspect Ratio, versus one using a 4:3 Aspect Ratio. Here is a handy chart that shows frame utilization at popular Print Sizes and Aspect Ratios:

http://home.earthlink.net/~terryleed....htm#frameutil

Quote:
Only the DSLR I've checked, the Powershot Pro1, have the correct ratio, I really don't get it...
I think you're mixing up the cameras you're looking at. The Powershot Pro 1 is not a DSLR model, and uses a 4:3 Aspect Ratio (which is the Aspect Ratio of the Sony 2/3" 8MP CCD used in this model).

The Canon Digital Rebel you're looking at is a DSLR, andusesa 3:2 Aspect Ratio (the Aspect Ratio of the Canon CMOS Sensor used in this model).

Now, some models using a CCD with a 4:3 Aspect Ratio can shoot in 3:2 Mode. Basically, they are simply cropping the image you see in the display and captured to files (they don't use the entire CCD Area for photos in 3:2 Mode). For example,other Prosumer Camerasusing the sameSony 2/3" 8MP CCD offer a 3:2 Mode (Konica-Minolta DiMAGE A2, Sony DSC-F828, Nikon Coolpix 8800), as well as a 4:3 Mode.

BTW, if you're only planning on printing at a 4x6" size, anything above about 2 Megapixels is going to be a waste (you won't be able to see any increase in detail or quaility by going to a camera with more than about2 Megapixels at this print size -- given equivalent image processing algorithms and lens quality). Although, you would have more room for cropping with higher resolution.

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Old Jan 6, 2005, 10:27 AM   #10
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Quote:

"BTW, if you're only planning on printing at a 4x6" size, anything above about 2 Megapixels is going to be a waste (you won't be able to see any increase in detail or quaility by going to a camera with more than about2 Megapixels at this print size -- given equivalent image processing algorithms and lens quality). Although, you would have more room for cropping with higher resolution."

I have been following this thread and have checked the link to print size/aspect ratio, etc. If I understand correctly, since I like to print larger format on my Canon i9900 the Canon 20D should fall within the acceptable range. Though the noise would be greater (?) the result should still be satisfactory. If I am correct, the choice of the 20D should be clearly better than the Nikon D70 if similar quality lenses are used. Yes?

Steve

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