December 2007 HelpLine

This Article Features Photo Zoom

• Step Up To A Larger Filter 
• Switching To A D-SLR
• Gray Area


Step Up To A Larger Filter

December 2007 HelplineQ) I’m about to purchase a 28-75mm lens for use with my digital SLR. It has a 67mm diameter lens; however, I have a 77mm circular polarizer that I would like to use with the new lens. I also plan to purchase a 67-77mm step-up adapter so that I can use these larger filters on the smaller lens. My question is, how will the quality of the image be affected by not using the exact size filter required, i.e., a 67mm polarizer on a 67mm lens?

Ron S. Surprise

A) Before I get to your step-up question, I want to clear up a common mistake when dealing with lens specifications. When you see a spec like 28-75mm, 10-22mm or 18-200mm, the measurements listed refer to the focal length of the lens.

If you ask me what size filter you should purchase to use with these lenses, I can’t give you an answer. (Well, I might be able to guess based on which manufacturers build zoom lenses with those focal lengths, but it would just be a guess.) The focal length of a lens doesn’t tell you anything about the filter size you need.

From your question, however, it’s obvious you know what size filter to use-you probably looked at the markings on the front of the lens. But I’d like to correct your terminology. When you mention you’re considering a 67mm diameter lens, that really isn’t accurate, although I understand what you’re saying. While there may (or may not) be an element in the lens that’s 67mm, the marking you see on the front of the lens indicates a filter diameter of 67mm. The ø symbol normally on the front of the lens next to the measurement indicates diameter.

Now back to whether there will be a problem using a different-sized filter. As long as you use a filter that requires a step-up adapter and not a step-down ring, you shouldn’t have a problem. I say “shouldn’t” because with some very wide-angle lenses, the step-up adapter may cause vignetting or darkening of the edges of your picture. In some extreme cases, this won’t be subtle. When you use a step-down ring for a smaller filter, the edges of the filter may appear in your image, depending on where you are in the zoom range of your lens.

The only other problem you might face is that your lens shade and lens cap won’t fit the larger filter. If you have the filter for use on a different lens, you can probably use that lens cap. Lens shades are designed for specific lenses, though, so you probably won’t be able to use a different lens shade on the new lens. 


Switching To A D-SLR

December 2007 HelplineQ) This question takes a recent question by Ed G., “A More Stable Lens,” a little further. I primarily use my digital camera for vacation photos to be put in slideshows. It’s nearly perfect, except since it’s not an SLR, I can’t see well what I’m shooting, especially in bright sunlight. In considering switching to a digital SLR, one of the things I don’t want to give up is the ability to take fairly decent photos in low light. I was able to take photos in the redwoods while it was raining slightly, something I couldn’t do with my film SLR.

What is it primarily that enables the camera to do this? Is it the image stabilization? Is it the fast ƒ/2.8-3.5 lens? Is it something inherent with digital SLRs, or is it a combination of all the above? In other words, how do I assure that a D-SLR I purchase will be able to take photos in low light?

A single 18-200mm digital lens is what I’m thinking about. I really don’t want to go back to changing lenses again. I especially don’t miss my big 400mm lens. Due to time constraints, I rarely use a tripod anymore, so image stabilization is a must.

L. Malott
Via the Internet

A) You’re referring to the October HelpLine where Ed G. was looking for a lens recommendation or, more specifically, advice as to whether it made sense to spend the extra money for a lens with stabilization. In my answer, I discussed ISO speed, use of tripods vs. handheld and bank accounts.

Now that was Ed, but you’re concerned about the performance of a digital SLR in low light. You mention you weren’t able to take photos in the redwoods with your film SLR. You probably could have, had you been using high-speed film.

One of the amazing features of digital cameras is the ability to change the apparent sensitivity of the camera’s sensor with just the press of a button—okay, so it might be a few buttons on some cameras! (I say “apparent sensitivity” because you’re really amplifying the signal coming from the image sensor—the sensor has only one native sensitivity.) This is something you could never do without changing rolls in a film camera. With high-speed film or a high-ISO speed setting on your digital SLR, your camera can work in lower light levels. With higher ISO speeds, you can also raise your shutter speed so you can handhold more shots with less blur.

Just like increased film grain with higher-speed films, there’s a trade-off with raising the ISO speed: noise. As you increase the amplification from the image sensor, you amplify noise in your image. But the low-noise characteristics of the latest digital SLRs are pretty amazing.

You also ask which part of the equipment equation allows you to take photos in low light: the fast lens, image stabilization or something inherent in the technology. Certainly, the faster the lens, the more light reaches the sensor, allowing you to photograph in lower light. Stabilization allows you to lower your handheld shutter speed, which also allows you to photograph in lower light. By coupling a fast lens, image stabilization and the ability to quickly change ISO speed, I think you’ll find that today’s digital SLRs will perform well in low-light situations and most likely will perform better than the compact digital camera you’re currently using.

One last word about time constraints not allowing you to use a tripod. If you have been following my columns, you know I’m a strong proponent of using tripods. But I realize that it can’t always happen. If time is an issue, consider using a monopod. They can be
quick to set up and easy to carry. While they don’t give you the complete stability of a tripod, they can help quite a bit.



Gray Area
Over the past few months, I’ve received several HelpLine e-mails regarding recommendations on where to purchase equipment. Some people ask whether it’s okay to buy online or by phone versus from a local retailer or camera store. Others want to know which site or store to use.

You can have successful purchases from a variety of vendors. When friends ask me about what camera to buy, however, I suggest they go to a store where they can put a unit into their hands so they can see how it feels and they can get used to where buttons are. Cameras are getting smaller and smaller and are loaded up with more and more features and buttons. If you plan to take a lot of pictures, it helps to have a comfortable camera that’s easy to use. You wouldn’t buy a car without a test drive, would you?

I’m not a fan of going to a camera store, having a salesperson go through the whole camera demo and then leaving and buying the camera online. If everyone did that, the store wouldn’t be around and then it might be difficult to actually touch a camera before buying it. But that’s just me.

One type of transaction I’ve cautioned people about, however, is the offer that seems too good to be true. If you compare prices and notice a seller who’s significantly lower than any other place, be careful. They may try to sell you additional “accessories” at an inflated price, or they may try to sell you gray-market merchandise.

Gray-market products are items manufactured for a different marketplace. They may be cheaper because, in another country, regulations are less stringent or tariffs and import duties are less. The non-gray-market (some would say “legal”) products may be more expensive because some of the marketing and support costs (like firmware upgrades) are built into the cost of the product.

Regardless of why something is cheaper or more expensive, the critical thing to watch out for with gray-market products is a lack of warranty coverage or repair service. Many manufacturers avoid servicing gray-market merchandise. 

If you have questions, please send them to HelpLine, PCPhoto Magazine, 12121 Wilshire Blvd., Ste. 1200, Los Angeles, CA 90025 or [email protected].


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