Minutes after fishermen tip him off that a ship is about to pass through Istanbul's Bosphorus, Yoruk Isik drops what he's doing and rushes to his favourite vantage point, camera in hand.
The vessel is not one of the dozens of cargo boats that pass through the strait between Europe and Asia every day. It is a Russian warship, in this case the landing ship Nikolai Filchenkov.
It makes stately progress through the strait towards the Sea of Marmara on a voyage that will eventually take it into the Mediterranean towards Tartus, Russia's naval base in Syria.
Isik clicks the shutter, capturing Russian sailors at the rails taking in the view. The Russians can be seen returning the favour, keeping a close eye on the shore-side observers.
Several Russian warships pass in both directions through the Bosphorus every week, transporting cargo for Moscow's military campaign in Syria, in a massive logistical effort known as the "Syrian Express".
Their passage through the densely-populated Turkish metropolis represents a unique chance to see close up a deployed Russian warship that would usually be kept well away from prying eyes.
And each time they come, a group of amateur but well-informed and hugely dedicated Turkish ship spotters are there to photograph them and share their work on social media where their following has shot up.
Their work rose to prominence in December last year when they spotted a Russian soldier aboard the Tsezar Kunikov warship with a MANPAD shoulder-launched missile aimed at the shore, in a gesture slammed as "provocation" by Ankara.
The pictures made headlines in Turkish media at a time of peak tensions between Russia and Turkey following the downing of one of Moscow's warplanes on the Syria border just 10 days earlier.
Standing by the old Ottoman fortress of Rumeli Hisari on the European shore of the Bosphorus where the strait is at its narrowest, Isik has been waiting for this particular Russian warship for several days.
Through his contacts and social media, he knows the vessel left Russia's Sevastopol base in Crimea -- the Ukrainian peninsula annexed by Moscow in 2014 -- several days before.
"That ship could have arrived as early as yesterday but it appears to have travelled slower because of bad weather in the Black Sea."
Isik says he can estimate the ship's arrival time soon after it leaves its base, but notes it might change depending on weather conditions or its tonnage.
"From Sevastopol to Istanbul, it is approximately 300 nautical miles. But the vessel may not always pass through the congested Bosphorus strait directly."
As the nose of the vessel emerges, he cracks a big smile, reminiscent of a small child opening a Christmas gift.
"Look, someone on the ship is saying hello to me," he says, pointing out armed Russian soldiers on board through the camera lens.
Like a nautical dictionary, Isik knows all of the technical specifications of this Tapir class tank-carrying landing ship -- when it was built, where it was used, how many military tanks it can carry.
An international relations specialist by profession, Isik is a passionate ship spotter, and only occasionally earns small amounts from the copyright of the pictures he takes.
"This is not a smart way to make money," smiles Alper Boler, another prominent ship spotter who has also enjoyed visibility after photographing Russian soldiers last December.
Boler usually takes pictures from his home in Uskudar, which has a beautiful view of the Bosphorus from the Asian side of the city.
Asked why he has been photographing ships for three years, his answer is simple: "Curiosity."
There was even a time when he would rush to shoot a passing ship during short breaks between business meetings.
"We are witness to whatever passes through the Bosphorus," says Boler who designs furniture and other products.
While it struck many outsiders as astonishing that Russian warships were passing unchallenged through the Bosphorus at the height of the 2015-2016 crisis between Turkey and Russia, it is a right enshrined in the 1936 Montreux Convention.
This gives the warships of Moscow -- and other Black Sea littoral states -- the right to pass so long as they are not at war with Turkey.
"It's not exceptional to see Russian ships for someone who grew up and who lives in Istanbul," Isik says.
"This is an exceptional location passing through a mega city, a narrow passage all the ships have to pass through, there's no other way around," he says, pointing to the Bosphorus.
Isik says the movement of warships through the Bosphorus is itself a sign of shifting international relations.
"Likewise, the presence of NATO ships here was a part of Europe's involvement in Ukraine-related developments with Russia."
But the traffic of Russian warships through the strait en route to Moscow's base in the Syrian port city of Tartus has dramatically increased in recent years, he says, especially since the Kremlin launched its military operation there a year ago.
"We predicted from August last year -- by merely doing ship spotting -- that Russia would launch an operation in Syria," he says.
But apart from all the war and politics, Isik says the Bosphorus is the place where he finds himself.
"Away from the reality of daily life, traffic, your child's school fees, that's the place I listen to myself."