lens - Same manufacturer, two lenses of similar focal length, but one is much faster...does the sweet spot produce the same resolution?

This has practical implications as I want to use a 300mm tele for shooting landscapes, where lens speed is not so critical but maximum resolution (and light weight) is. Would I drop twenty times the coin and haul twice the weight for similar resolution if I bought the faster lens?

Let's take this example: let's compare a Canon 300mm 2.8 to a Canon 300mm f4. According to their specs, the f2.8 has 17 elements in 13 groups and weighs about 5 lbs, whereas the f4 has 13 elements in 11 groups and weighs about half as much. The price difference is also very substantial. Does what I'm looking for reside in DxO's MTF data for these lenses? If not, where might I find data that helps me compare resolution as a function of aperture for these two lenses?

Answer

Same manufacturer, two lenses of similar focal length, but one is much faster…does the sweet spot produce the same resolution?

Short answer: Maybe. Maybe not.

It all depends on each individual lens.

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The sweet spot of a lens is dependent upon the individual design and execution of the lens.

You could even have two lenses of the same focal length and maximum aperture with different designs and the sweet spot would not necessarily be at the same aperture for both lenses nor would the resolution at one lens' sweet spot necessarily be the same as the other lens' resolution at its sweet spot.

It all depends on the specific lenses in question.

There are a few lenses that are "over designed" and just as sharp wide open as they are any other aperture.
Most lenses are sharpest about two full stops down from wide open.
Some lenses are sharpest in the center at a different aperture than they are sharpest on the edges and in the corners.

It all depends on the specific design of the lens.

The sweet spot of one lens could also be worse than the worst aperture setting of another lens. If one lens costs twenty times the other it quite possibly might be better at every aperture than the cheaper lens is at any aperture.

Rather than comparing what aperture is the sweet spot of each lens, you should probably consider how each lens performs compared to the other lens at the aperture you plan to use it the most.

It all depends on the two individual lenses.

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Now that the specific lenses have been revealed we can look at the question in more detail. They are all very good, but there are measurable differences.

The results below are when tested by DxO Labs mounted on the Canon EOS 1D X at each "full stop" aperture setting. The actual "sweet spot" of each lens may be at an intermediate 1/3 stop setting, but it won't be very much different than the nearest whole stop.

The EF 300mm f/4 L IS is sharpest at around f/8 At that aperture it is roughly equal to the EF 300mm f/2.8 L IS used wide open at f/2.8. It is not as sharp as the newer EF 300mm f/2.8 L IS II at f/2.8.

The EF 300mm f/2.8 L IS is sharpest at f/5.6 At f/5.6 it is sharper than the EF 300mm f/4 at f/8 from the center of the frame out to about 60% of the frame on a FF camera (which would be the very edge of the frame on an APS-C crop body). It is about equal to the EF 300mm f/2.8 L IS II set to f/4 at the center of the frame but past about 35% of the frame (35% FF camera - about 60% on an APS-C camera) the resolution begins to drop off a bit.

The EF 300mm f/2.8 L IS II is sharpest at f/4. It is only very slightly less sharp wide open at f/2.8 and at f/5.6. It maintains the level of resolution fairly consistently all the way from the center to the edges at all apertures until diffraction begins to set in around f/8

At f/8 all three lenses are very close in resolution at the center but the EF 300mm f/2.8 L IS II is measurably sharper at the edges of the frame.

At f/5.6 the differences are more pronounced: The two f/2.8 versions are equally sharp in the center of the frame, the two older lenses are about the same on the far edges of the frame. The EF 300mm f/2.8 L IS is somewhere between the other two from about 35% of the frame until just before the edge of a full frame sensor.

When tested on the higher resolution EOS 5Ds R, the EF 300mm f/2.8 L IS II pulls away from the older f/2.8 and the EF 300mm f/4 falls away from both when all lenses are wide open. The resolution numbers for all three lenses are higher with the much higher resolution camera, but the comparisons between each lens at each's respective sharpest aperture holds.

Here are the resolution profiles of the three lenses when measured by DxO on the Canon EOS 5Ds R with each lens set at its sharpest aperture:

When mounted on the smaller APS-C sensored, lower resolution EOS 7D Mark II the newer EF 300mm f/2.8 L IS can't use the edges of the image circle (which are cropped off by the smaller sensor) to pull away from the older EF 300mm f/2.8 L IS. But they are both still measurably sharper than the EF 300mm f/4 L IS.

Comparative results for the three lenses on older, lower resolution APS-C bodies are similar. As the resolution of the camera used to test them is lowered the scores for each lens drop but their relative performance remains fairly constant.

The EF 300mm f/4 L IS weighs about 2.63 pounds/1190 grams, was introduced in 1997, and currently runs about $1,350 in the U.S.

The EF 300mm f/2.8 L IS weighs about 5.63 pounds/2550 grams, was introduced in 1999 and was discontinued by Canon upon the introduction of its replacement in 2011. It can be found on the used market for about $2,500-3,000 in the U.S. for a copy in very good to excellent condition.

The EF 300mm f/2.8 L IS II weighs about 5.19 pounds/2350 grams, was introduced in 2011, and currently runs about $6,100 in the U.S.

Only you can decide if the better resolution of the EF 300mm f/2.8 L II is worth enough to offset the 4.5X cost and 2X weight compared to the EF 300mm f/4 L IS.

Please Note - There are older, non-IS versions of the EF 300mm f/4 L and EF 300mm f/2.8 L. These are older lenses with different optical formulae than their newer IS counterparts. The older, non-IS lenses have not been tested by DxO Labs. Testing sites who have tested the older and newer versions show measurable improvement with the newer IS versions over their older counterparts.

Also, don't even think about using the EF 75-300mm f/4-5.6 at 300mm in comparison to the 300mm primes. The EF 70-300mm f/5.6 IS does get pretty close to the EF 300mm f/4 at 300mm and f/8. The EF 70-300mm f/4-5.6 IS was introduced in 2005, weighs 1.4 pounds/630 grams, and can currently be bought new in the U.S. for about $450 ($650 list) as the brand new EF 70-300mm f/4-5.6 IS II ($550 - not yet tested by DxO) has just replaced it in Canon's lineup.

noise - Why does raising ISO make image quality appear lower even though my measurements suggest it shouldn't?

I know this may be rehashing one of the most discussed topics, but I would like to take it a slightly different direction and solicit input. First of all, I am familiar with the electrical engineering and mechanisms associated with changing the camera gain, normally described in the DSLR community as ISO. I understand that it is changing the capacity of the electron well, which leads to a faster sensor for each pixel/photodiode. However, what I am trying to rationalize is theory vs. reality.

I have done due diligence with my Canon 70d and 6d and measured the read noise, thermal noise as a function of time for various stagnant ambient temperatures, measured the gain in electrons per ADU at most ISO's, determined the electron well size in photons per ADU and most importantly, made analogous measurements of the signal to noise ratio for various exposure times (in a dark frame) at various ISOs. In my measurements, as theory would predict, while the noise does increase as a function of ISO, the signal to noise ratio increases.

This would lead one to believe that for properly exposed high ISO images in post processing, while you may loose some signal effects by stacking, subtracting bias and dark-thermal frames and adjusting the luminance channel, that you will still come out with a superior image due to the fact you started out with much more signal-effect than noise. However, reality has consistently presented a different situation, where as my ISO increases the best image I can achieve after post processing is in many cases inferior to what was produced at a lower ISO, especially if shooting time-lapse where stacking and frame subtraction are much more impractical. For crop frames I have found that I can never get above ISO 1000 and for full frame cameras, I have a hard time getting above ISO 2500 without inducing granularity that looks un-natural, despite the fact I see many people shooting at 25,000 and higher. I would love to hear comments are explanations from any interested people describing why the higher signal to noise ratio rarely translates to a better image, or rebuttals to this idea if anyone has one.

What printer should I get to replace an epson r800?

I've looked at the Master's Thesis discussion on printers, but I'm interested in a more practical, here-and-now kind of thing. I haven't looked at printers recently, and reading reviews on CNet and the like doesn't tell me the things I want to know.

I need a printer that can:

• print up to 10x15 or 12x12


• ideally, not suck down ink like I suck down beer


• use alternative papers (Hahnemuhle, etc)


• ideally, require little to no calibration, or be easily calibrated


• produce prints that I would be proud to sell.

For the longest time, my r800 did the third thing and the last thing (but only the last thing when I spent an hour or so fine-tuning the output). I need something bigger now, and something that takes less draft printing to get to a good final result.

What should I be looking for? Budget is less than $1k.

Answer

This is a difficult question to answer, as it is fairly subjective. Both Epson and Canon printers are excellent, and provide astonishing quality. I'll try to avoid the culture war here, so here are some basic statistics and important points about printers that meet your needs:

1. One of the first things you need to decide is how valuable quality is to you:
   
   
   
   • The base cost of the printer is minimal compared to the long-term running cost
     
     
     
     • Cleaning and maintenance have an intrinsic cost due to ink usage and part replacement
     
     
     
     
   
   
   • Ink is the most costly part of creating your own prints
   
   
   
   
   


2. Determine how long you hope to use your printer:
   
   
   
   • You may want to print 10x15 and 12x12 now, but what about the future
   
   
   • Will you ever need to print 17x22?
   
   
   • Will you ever need to print panoramics (i.e. roll paper)?
   
   
   
   


3. What is the minimum quality bar you require:
   
   
   
   
   • If you intend to sell your prints, what you percieve as acceptable may be a far cry from what your customer percieves as acceptable
   
   
   • Does the printer you are looking to buy produce adequate resolution and tonal range to be "acceptable" to your customers?
   
   
   
   


4. How long do you expect your prints to last?
   
   
   
   • Some papers and inks last for a few decades
   
   
   • Some papers and inks last for hundreds of years (theoretically)
   
   
   
   

Both Canon and Epson printers can serve your needs. Canon offers two types of professional photographer printers that use different types of ink. Epson printers all use the same type of ink, but offer progressively greater versatility in terms of paper sizes and variety, and some of the higher-end models produce some extended tonal range into areas even computer screens can't reach (i.e. deep vivid purple hues.)

When it comes to Canon, you have a choice between the PIXMA series, and the ProGraph series. The PIXMA series offers two printers, the 9000 and the 9500 Mk II. The 9000 uses dye inks, which are generally cheaper and do not dry out as easily, and are extremely economical. The ultimate tonal range and longevity of dye prints is generally on the lower end. The 9000 uses 8 individual ink tanks, allowing colors to be individually replaced.

The 9500 uses 10 pigment inks, including several black/gray shades for B&W printing. Pigment inks generally produce more accurate tonal range, and the longevity is up in the 105-200 year range. Pigment inks are generally preferred for archival and professional prints, however they do come at a greater cost. Pigment inks have a greater tendency to dry out if not used, and dry pigment ink can clog a print head, which generally costs about $120-$160 to replace. Canon ink tanks for the 9000/9500 are about 14ml in size...extremely small. These ink tanks do not last for a very long time, and the ratio of waste is fairly high. This increases the cost overall.

The Prograph series of Canon printers are a step up. They are generally geared towards the truly professional photographer and business class. All of the current Canon Prograph printers use the same Lucia pigment ink that the 9500 does. The advantage these printers have over the 9500 is greater paper size versatility (up to 17x22 or beyond) and considerably larger ink tanks. Lower end Prograph printers use 80ml ink tanks, and higher end (truly business class, probably well out of your interest range) use 160ml tanks.

When it comes to Epson, all of their printers use their stellar UltraChrome K3 pigment inks. Epson printers tend to use a higher native print resolution than Canon printers, however they have a lower DPI. Like the Canon 9500, the ink tank size for the lower end of their Stylus line are about 15ml, and like Canon this increases cost due to general operating waste. Higher end Epson Stylus printers use larger ink tank sizes, and offer the same benefit that the Canon ProGraph line does. One of the benefits of Epson is greater paper versatility. Epson provides an extremely diverse line of papers, including paper roles for panoramic and banner printing (up to several feet long.)

HP is also an alternative, as they also make a professional photography printer. I've read reviews about HP printers, however I have never used one, and can no personally provide an objective review of their capabilities. I would look into some reviews if you are interested, however Epson and Canon are the top dogs in the professional photo printing arena.

Alternative papers may be used on either Epson or Canon printers. Canon fine art papers are in actuality just Hahnemuhle under the Canon label. I use a Canon 9500 MkII myself, and I use the Hahnemuhle ICC profiles for Fine Art, Museum, and Matte papers, which produce significantly better results than the Canon default ICC profiles.

Before you make a decision, I highly recommend seeing if you can print some of your own work on a couple different Epson and Canon printers. Determine if you yourself like the results, and see what some of your potential customers (or friends/family who you think are similar to your potential customers), and choose the printer that best fits you and your potential customers needs. The Canon PIXMA Pro 9000 runs around $400 or so, while the PIXMA Pro 9500 is about $600-$700. Canon Prograph printers run from around $1200 to many thousands of dollars for the top end business class. The iPF5000 or iPF6000 series are at the lower end of that price range, and are very efficient printers. Epson Stylus printers run anywhere from about $500 up through $4000 or more.

special effects - Is there a camera which can superimpose a subject onto a predefined background?

Let's say I have an image of the Taj Mahal.

I want set the above image as my background image when taking the picture. Something similar to Photo Booth effects available in OS X, where you'll be asked to step out of the frame, then once the image is setup as the background, you'll be prompted to step inside the camera view.

Is there any camera that supports this effect?

Do I need a model release to post a photo on an online portfolio?

I was in a park yesterday snapping photos. Though focused on landscapes and nature shots, I happened to get a photo of a woman in the park and it turned out to be a nice photo. She was hundreds of feet away and I wasn't prepared with model releases or anything, so I didn't bother running after her. I'd like to post the photo on my SmugMug portfolio. I don't plan on selling the photo or using it in any other manner. Will posting it on an online portfolio get me into any kind of trouble? Am I better off just leaving the photo on my hard drive?

Answer

This is a legal question which you should ask a lawyer to be certain. Given that SmugMug is in the middle, you may want to check with their terms of service, too. The particular legalities will depend on where you live and where the photos are hosted.

As a general rule, if you have to ask then you should get one. On the other hand, the likelihood that you get into trouble is proportional to your perceived ability to pay.

You may simply be asked to take down the photo and I do not think much damages would be claimed if there was no commercial gain for you or SmugMug. You definitely need a release if your page has ads or offers prints, regardless if it is you or your provider doing the printing.

travel - Looking for a discreet camera bag

I'm off next week on a bit of a world trip for 12 months. Any suggestions for a camera bag solution that meets the following (in order of importance):

1. Discreet. Must not look like it has an SLR in it ;)



2. No expensive logos (eg "krumpler" or "lowepro" etc. even though I like them)


3. Can carry bare essentials (camera body with 1 lens attached + speedlite + bottle of water + banana)


4. Will keep camera dry in rain


5. Two shoulder straps as will be carrying it every day


6. Light as possible


7. Suitable as hand luggage when flying

DIY solutions also welcome if quick and easy to do (running out of time)

Cheers,

Matt

Answer

There are a variety of padded camera bag inserts available at online stores like B&H for very little money that you can fit into a non-camera bag that you can buy elsewhere. I found a bag at an Army Navy store that fit mine perfectly. Photos: http://blog.muddyboots.org/2007/08/diy-stealth-camera-bag.html

That bag is not waterproof, but I carry a garbage bag to put it in in case of rain. I'm not sure where you could find a waterproof bag, but you can try.

Another idea is a cooler or diaper bag -they often provide a little padding and they make some nicer looking ones these days.

How can I use live view while tethering a Nikon D810 to LightRoom 5 CC?

My camera is a Nikon D810. I have the Adobe Creative Cloud suite and haven't updated it for a while, but my Lightroom version is 5.

My camera came with a cable, one side was a HDMI I think that I connected to port of the camera and the other side was a USB cable that I connected to the laptop and opened Lightroom, and was able to take pictures with the viewfinder of the camera and they showed up but I can not get LiveView of the camera to turn on and use that instead of viewfinder.

I want LiveView so I can zoom in on my focus point and exactly see if I am tack sharp or not.

Answer

Lightroom don't support tethering with live view for Nikon cameras. If you want to use tethering with live view you need a another application like Camera Control Pro, ControlMyNikon or a freeware digiCamControl or any similar application.

You can use external application with lightroom with no problem if you activate the Auto Import feature