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cams May 8, 2006 3:03 PM

I've finally decided on the Nikon D50, thanks to the response from all of you. Now for the lens. I need as much zoom as I can get for wildlife pictures and macro for the flowers. I was looking at the Tamron AF18-200mm with macro or the AF28-300mm with macro. The macro feature on the lens would help from all the changing of the lens in the field. Is the 28mm versus the 18mm much different that it would be a problem? They say that the 28mm isn't a digital lens. Is that going to show up on the pictures? Is there something beterout there that I'm missing? Thanks for your imput.

robbo May 9, 2006 3:17 AM

I have a Sigma 28 - 300 mm zoom lens with macro for a Pentax mount (*ist DS). It's ok for the money ($141 counting shipping on Ebay). These "big range" superzooms are not popular with mostserious photographers. It's too hard for a singlelens to produce top quality images throughout the entire zoom range. Most would probably advise to buy at least 2 separate lenses, one for wide angle and one for telephoto. I don't know enough to tell you which lenses are the best. However, if you specify how much money you can spend, others probably can.

Almost all digital SLR's have a crop factor when used with regular SLR lenses. Thus, a 28mm to 300mm range on a regular film SLR could end up being like a 42 to 450mm lens. That's great for telephoto shots, but not so great for wide angle shots.

It might be as cheap to leave your macro shots to a good point and shot, like the Canon A610 (under $200 online now).

E.T May 9, 2006 3:35 AM

Yep, that first would be much better as general/all in one travel lens because after "crop" factor it gives roughly 28-300mm range.

RightyInc May 9, 2006 6:56 AM

Because the Digital sensor is smaller than a 35mm film frame, there is a tele conversion that happens with every lens you put on a DSLR. The general magnification is 1.5 or 1.6 - depending who you talk to.. i like to use 1.5 because it makes it easier to work out in my head, haha. So a 28mm lens would actually work out to be a 42mm lens. Which means that nice 28mm wide angle you had, is now gone. This is why "digital" lenses start at 18mm, so that with that magnification it works out to ~27mm.

Now, that's jsut the basics, howver there is a difference to a "digital" lens and a "film" lens, I don't know all the technical issues, but it has something to do with the way the lens is coated, so that the lights is more direct onto a smaller surface area rather than spreading it to a full 35mm frame - in canons this is the 'EF-S' lens mount.

On that note, most people probably wont notice the difference between a 'film' lens or a 'digital' lens, I guess the main factor being that 18mm wide angle, in telephoto it really doesn't matter. If you want to use that lens for tele macro, then you'll ahve no issue, if you want it for an every day lens, look at something that starts around 18mm. But then, I'm assuming you're keeping the standard 18-55 that came with your camera anyway?

JohnG May 9, 2006 11:48 AM


a 'digital lens' could refer to one of two concepts:

1. Somg SLR lenses add a special coating to reduce lens flare that is more prominant because of a digital sensor as opposed to the same lens on a film camera. So, this extra coating could be one aspect of a 'digital 'lens'

2. Other folks have mentioned the 'crop factor' of a digital SLR. The crop factor is due to the fact that the digital sensor is smaller than 35mm film. It is not a question of 'who you ask' - it is a question of which manufacturer made the camera. Canon 300d, 30d, 20d have a sensor size that equates to a crop factor of 1.6. The Canon 5d has no crop factor, the Canon 1dkMKII N has a 1.3 crop factor. Nikon uses sensors with a 1.5 crop factor on all it's DSLRs. Atleast one other manufacturer (I forget which) has a 2.0 crop factor sensor. The crop factor occurs because the light coming through the lens is larger than the image sensor - SLR lenses were designed to cover a 35mm image. Now, because of the smaller sensor sizes, manufacturers have started to create lenses specifically designed for the crop sensor - they can use smaller optics that generate an image size for that crop size. As an example, Canon's EF-S lens line was developed for their 1.6x crop factor cameras. The lens is smaller and costs less for canon to make than a corresponding lens for film. The benefit to the user is that it is lighter, and eventually it will be less expensive. The downside is those lenses don't create an image large enough for sensors with a smaller crop factor than 1.6. So, if you tried to use an EF-S lens on the 5d, you would see dark around the edges (if the lens would even mount). This is the other digital-specific modification to lenses.

Some people, and I'm one, are leary about that second category - just because I have a 1.6x crop factor camera now, I might have a full size sensor camera 3 years from now - I don't like the fact the lens would be useless on that camera. Other people are not so concerned.

mtclimber May 9, 2006 1:49 PM

1 Attachment(s)

The so called digital lens is specifically designed for the smaller 13 X 26mm APS-C imager used on the D-50. I own and useboth the Tamron 18-200mm XR Dii lens and the Tamron 28-300mm XR Di lens on my Nikon D-50. The 18-200mm is the better lens, but when you need the longer reach, the 28-300mm sure comes in handy. If you could only manage one lens, then I would go with the Tamron 28-300mm lens. I have attached a photo sample from the Tamron 18-200mm lens.


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