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Old Mar 4, 2005, 7:58 AM   #1
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I am considering buying the Olympus c-7070 as I really need the 28mm equivalent lens for scenic shots (I am about to travel Europe for 5 weeks) - and it's supposed to be a pretty good camera! However, some people have noted that the f2.8 lens has led to some problems focussing in the (similar but superceded) c-5060 when compared to the c-5050 (f2.0). As a user of an old OM-10 for many years, I was also concerned about such a loss inlight gathering ability (albeit at maximum wide angle).

I got the impression from some threads that digital SLR was almost always a better choice if you can afford it: my problem (?)is that most digital SLR's that I have seen for sale with 28mm equivalent lenses have a maximum aperture of only f3.5.

My question on this point is therefore limited to: Is the c-7070 at f2.8 a better choice for low-light situations (eg. indoors without a flash) than a digital SLR at f3.5? (I am assuming full manual control for both cameras and the same MP)

ps. If this has been covered somewhere before, please direct me to the thread but I have searched in these forums and have not been able to find it.
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Old Mar 4, 2005, 9:00 AM   #2
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Wiggy wrote:
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I got the impression from some threads that digital SLR was almost always a better choice if you can afford it: my problem (?) is that most digital SLR's that I have seen for sale with 28mm equivalent lenses have a maximum aperture of only f3.5
Not quite!

Just 1 example - http://www.sigmaphoto.com/lenses/len...85&navigator=6
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Old Mar 4, 2005, 9:09 AM   #3
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Which is the meaning of the word "most" - I did not say "all" - do you have anything helpful to say?
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Old Mar 4, 2005, 9:09 AM   #4
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It depends on the way you're going to be taking the photos (with or without a tripod, etc.).

If you're going to try to take photos without a flash or tripod indoors, then you're going to find that any of the prosumermodels with a lens starting out at f/2.8 is going to produce borderline photos at best. But, the 7MP 1/.8" CCD used in a model like the C-7070WZ, has lower noise levels than prosumer models using the 5MP 1/1.8" CCD. So, even though it's lens may not be as bright as a model like the C-5050z, it works better as ISO speeds are increased. So, they are probably "a wash" in low light.

In most indoor lighting, you'd need to shoot at ISO 400 and f/2.8, just to get shutter speeds fast enough to prevent motion blur from camera shake without a tripod or flash. If your subject is not absolutely stationary, ISO 400 may not be enough to reduce motion blur from subject movement (and ISO 400iswhere most prosumer models "max out" ). You can also expect a significant amount of noise at ISO 400 with a prosumer model (due to their tiny sensors).

A DSLR uses a much larger sensor, and can shoot at higher ISO speeds compared to a prosumer model. As a result, there is really "no contest" between the two camera types for existing light shooting (if you're not using a tripod).

If you are using a tripod, and your subject is stationary, then a prosumer can perform the task in many indoor conditions. You can keep ISO speeds set low (to reduce the appearance of noise), with the tripod preventing motion blur from camera shake.

If you're not able to use a tripod or flash (and/or your subject is not stationary), then the DSLR would be a much better choice. Chances are,noise levels with most DSLR models would beabout the same at ISO 1600, as a prosumer model would be at ISO 400 (for most, but not allDSLR models - for example the newer Olympus E-300/EVOLT may not have that much difference due to it's smaller Kodak sensor).

So, the less than one stop difference you'd have between f/2.8 and f/3.5 would give the advantage to the DSLR, because of it's lower noise levels.

Also keep in mind, that withmost DSLR models, you will need to contend with a crop factor (a.k.a., focal length multiplier). Even though the sensors used in DSLR models are dramatically larger than the sensors used in prosumer models, they are stillsmaller than 35mm film.

As a result, your angle of view is different. To get the same apparent angle of view on a DSLR model as you'd have on a 35mm camera, you need to use a "crop factor" as a multiplier. For example, this factor is 1.6x on the Canon DSLR models. So, you'd need an 18mm lens to get a focal length equivalent to approximately 29mm on a 35mm camera model (18mm x 1.6 = 28.8 ).

So, make sure you take the crop factors (a.k.a., focal length mulitpliers) into consideration when buying lenses. For most (but not all) Canon DSLR models, this factor is 1.6x. For Nikon and Pentax DSLR models, this factor is 1.5x. For the Sigma models, this factor is 1.7x. For the Olympus models (which have the smallest sensors of any of the current DSLR offerings), this factor is 2.0x.

Now, for indoor photos without a flash (unless your subjects are stationary and you're using a tripod), I'd strongly consider going with a brighter lens, even with a DSLR. Otherwise (depending on your use for the photos), you may find that noise is objectionable at the ISO speeds you may need to prevent motion blur (for moving subjects, it's not uncommon to see ISO 1600, or even ISO 3200 used).

Bright primes are popular for this purpose (50mm f/1.4, 50mm f/1.8, etc).

There are pros and cons to both types of cameras. The DSLR models will focus faster, give you more flexibility (thanks to a wide variety of lenses), have lower noise levels, etc.

But, they are larger and heavier solutions. Depth of Field is another thing to take into consideration... Because the sensors on non-DSLR models are very small, the ac tual focal length of the lenses are very short for any given 35mm equivalent focal length. As a result, you have much greater depth of field for any given 35mm equivalent focal length, aperture, and focus distance.

If you're going to be taking photos where you want more of an image in focus as you get further away from your focus point, then a prosumer model is a better choice.

However, if you want to take photoswhere you want to be able to use a larger aperture (represented by smaller f/stop numbers) so that your subjects stand out from distracting backgrounds (i.e, you want a shallow depth of field), then a DSLR is a much better choice.

For any kind of action shooting where focus speed, cycle times between photos, etc., is involved, the DSLR is going to be your best bet.

There are many pros and cons... The DSLR is a much more expensive proposition (especially when you factor in the cost of lenses). But, these lenses become an investment. So, when you upgrade your camera body later, chances are, you can take your lenses with you within a manufacturer (unless they make a major lens mount change).

On the other hand, most users tend to like the "straight from the camera" photos more from non-DSLR models. That's because they tend to process the images more (sharpening, contrast, saturation, etc.). In contrast, DSLR models tend to give you more true to life images, that most users may find to be a little "bland". As a result, you can expect to post process the images using software for best results with most DSLR models.

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Old Mar 4, 2005, 9:43 AM   #5
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Thanks JimC - I read about the crop factor which is why I was very careful about which cameras and lenses made it to my final list of possibles. It's very important that I have at least a 28mm equivalent lens, and that it is capable of shooting indoors without blur (and without having to use a computer to try to compensate for lack of detail in the original image). Considering the cost of the (once-in-a-lifetime)holiday, I don't want to end up regretting the photos in 20 years time, so cost is not that much of an issue for the camera and lens.

What is the brightest 28mm equivalent lens currently available?

You have also raised another point which I thought was obvious but I have not been able to find a definitive answer for: Does a physically larger CCD produce a better image than a smaller CCD if both are rated at the same MP?
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Old Mar 4, 2005, 10:33 AM   #6
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Wiggy wrote:
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What is the brightest 28mm equivalent lens currently available?
I don't know...

There are many lenses on the market now. A quick glance at some lens charts leads me to believe that it's going to be tough finding anything brighter than f/2.8, if you need a 35mm equivalent focal length of 28mm in an entry level DSLR (since most will have a crop factor). There are only a handful of DSLR models that don't have acrop factor, and these are rather "pricey" (for example, the Canon EOS-1DS andCanon EOS-1DS Mark II).

If you can compromise on your need for both wide angle and a bright lens (in the same lens), then you can find some primes that are a stop ortwo brighter (Sigma 20mm f/1.8, Canon 24mm f/1.4L, etc.).

But, keep in mind that most lenses area little softer shooting "wide open", too. Another thing to remember, is that Depth of Field is going to be very shallow shooting wide open.

These lenses also tend to be pricey... For example, the Canon 24mm f/1.4L (which would give you a 35mm equivalent focal length of approximately 38mm on most Canon DSLR models) sells for approximately $1,100.00 discounted.

The Sigma 20mm f/1.8 is under $400.00 discounted, and it would give you a 35mm equivalent focal length of approximately 32mm on most Canon models, or around 30mm on Nikon or Pentax models.

As a general rule, Zoom lenses this wide are going to start out at f/2.8 or so.

Once you narrow down your choice of cameras, you may want to visit the lenses forums here and ask for opinions on what's available for a given model.

Quote:
You have also raised another point which I thought was obvious but I have not been able to find a definitive answer for: Does a physically larger CCD produce a better image than a smaller CCD if both are rated at the same MP?
Better is subjective...

Unless you need larger prints, Megapixels is probably one of the factors I'd give the least weight to. Many other things are usually more important (lens quality, features, ergonomics, control/menu layout, autofocus speed/reliability, cycle times between photos, contrast, color, saturation, noise levels, etc.).

The problem with a smaller sensor, is that they have smaller photosites for each pixel. As a result, more light is required for equivalent ISO speed sensitivity. So, you need to amplify the signal more from a smaller sensor, which results in higher noise levels.

As a result of the "megapixel race", many new models, IMO, produce worse photos than some of the older, lowerresolution models at anything above the lowest ISO speed settings. This is because manufacturers have been stuffing more and more photosites into smaller and smaller sensors.

Even when sensor sizes have remained the same, due to more photosites (to get higher resolution), image quality can be worse with some newer models as ISO speeds are increased. IMO, the older 2 and 3 Megapixel 1/1.8" CCD sensors produced better images as ISO speeds were increased, compared to the newer 5MP 1/1.8" Sensors (because the photosites for each pixel have been getting smaller as manufacturers try to stuff more of them in). Most consumers equate higher resolution with higher quality. Well, that's not always the case.

On the other hand, advancements are being made (image processing algorithms, lens quality, etc.) in prosumer models. So, this can help to offset the downside of hgher resolution in smaller sensors.

IMO, Sony also made some advancements in the design of the new 7MP 1/1.8" CCD (as used in the Olympus C-7070WZ). So, it appears to have lower noise levels compared to the 5MP 1/1.8"CCD that proceeded it.

Smaller sensors also tend to have lower dynamic range (the ability to distinquish both light and dark areas of an image). Although, this part is controversial, and I have not seen anyone that's been able to accurately measure this yet to everyone's satisifaction.

Another thing to consider is that manufacturers tend to use faster processors, larger buffers, etc., in DSLR models versus prosumer models. But, as I mentioned before, the images are not typically processed as much either. This is a good thing to many critical users, since you have more control over the image processing later with software. But, many consumers don't want to be bothered with post processing. So, there are pros and cons to both camera types.


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Old Mar 4, 2005, 11:02 AM   #7
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Wiggy wrote:
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What is the brightest 28mm equivalent lens currently available?

Olympus will have some F2 zoom lenses available latter this year with one being a 14-35mm (equil to 28-70mm in 35mm terms) constant F2 for the 4/3 mount. Unfortunately because they are the only manufacture to offer an F2 zoom they can price them where they please (ie: not going to be cheap at all!).:sad:
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Old Mar 4, 2005, 11:14 AM   #8
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Wiggy wrote:
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Which is the meaning of the word "most" - I did not say "all" - do you have anything helpful to say?
1. Certain cameras have the capability to focus more accurately with an f/2.8 lens (it's more precise because the DOF is shallower)

2. The other benefit of the extra f-stop is during sunrise/sunset where movements are involved such as for waves or windy leaves... during early/late hours

3. Here's another one - (and it'll go on most dSLRs)
http://www.sigmaphoto.com/lenses/len...58&navigator=1
Check the MTFs they are quite good up to 13mm the limit of the crop sensor!
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Old Mar 4, 2005, 1:26 PM   #9
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Wiggy wrote:
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Which is the meaning of the word "most" - I did not say "all" - do you have anything helpful to say?

A dSLR can take any current lens made for the same company's film SLR. Your premise that you would be limited to f3.5 lenses is false. The 'kit' lenses that come bundled with any consumer SLR, film or digital, tend to be crap.
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Old Mar 4, 2005, 4:34 PM   #10
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If you can hack going to film there are some excellent buys on e-bay for older Yashica Electro Rangefinder cameras. You will not get your 28mm aperature but they will give you a 1.7 aperature for some of the best hand held low light and low cost mix you could ask for. As for another film choice there is the excellent Yashica/Comtax T-4 pocket cameras they do have 28mm aperatures. These are very popular cameras. I am very pro digital, but it always seems that while I can get a picture out of a low light scene it never has the detail needed for a really good photo. The best shot have been using the limited range of the focus assist lamp.
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